https://github.com/CGAL/cgal
Revision 2f890ac71124f2d8f0f0be4e900c9ecdb37018f4 authored by Sébastien Loriot on 02 July 2015, 12:20:23 UTC, committed by Sébastien Loriot on 02 July 2015, 16:47:15 UTC
on the elephant subdivided 3 times with loop, it required 60s.
vs 40s. with the linear alternative
1 parent 8efbac7
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Tip revision: 2f890ac71124f2d8f0f0be4e900c9ecdb37018f4 authored by Sébastien Loriot on 02 July 2015, 12:20:23 UTC
remove the version using the edge simplification package
Tip revision: 2f890ac
changes.html
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<H1>Release History</H1>

<HR>

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<tr>
<td width="2%">
<td width="28%">

<table CELLSPACING=0>
<tr><td><a href="#release4.7">4.7</a>&nbsp;<td> (September 2015)
<tr><td><a href="#release4.6.1">4.6.1</a>&nbsp;<td> (June 2015)
<tr><td><a href="#release4.6">4.6</a>&nbsp;<td> (April 2015)
<tr><td><a href="#release4.5.2">4.5.2</a>&nbsp;<td> (February 2015)
<tr><td><a href="#release4.5.1">4.5.1</a>&nbsp;<td> (December 2014)
<tr><td><a href="#release4.5">4.5</a>&nbsp;<td> (October 2014)
<tr><td><a href="#release4.4">4.4</a>&nbsp;<td> (April 2014)
<tr><td><a href="#release4.3">4.3.1</a>&nbsp;<td> (November 2013)
<tr><td><a href="#release4.3">4.3</a>&nbsp;<td> (October 2013)
<tr><td><a href="#release4.2">4.2</a>&nbsp;<td> (March 2013)
<tr><td><a href="#release4.1">4.1</a>&nbsp;<td> (September 2012)
<tr><td><a href="#release4.0.2">4.0.2</a>&nbsp;<td> (July 2012)
<tr><td><a href="#release4.0.1">4.0.1</a>&nbsp;<td> (July 2012)
<tr><td><a href="#release4.0">4.0</a>&nbsp;<td> (March 2012)
<tr><td><a href="#release3.9">3.9</a>&nbsp;<td> (September 2011)
<tr><td><a href="#release3.8">3.8</a>&nbsp;<td> (April 2011)
<tr><td><a href="#release3.7">3.7</a>&nbsp;<td> (October 2010)
<tr><td><a href="#release3.6.1">3.6.1</a>&nbsp;<td> (June 2010)
<tr><td><a href="#release3.6">3.6</a>&nbsp;<td> (March 2010)
<tr><td><a href="#release3.5.1">3.5.1</a>&nbsp;<td> (December 2009)
<tr><td><a href="#release3.5">3.5</a>&nbsp;<td> (October 2009)
<tr><td><a href="#release3.4">3.4</a>&nbsp;<td> (January 2009)
<tr><td><a href="#release3.3.1">3.3.1</a><td> (August 2007)
<tr><td><a href="#release3.3">3.3</a><td> (May 2007)
<tr><td><a href="#release3.2.1">3.2.1</a><td> (July 2006)
<tr><td><a href="#release3.2">3.2</a><td> (May 2006)
<tr><td><a href="#release3.1">3.1</a><td> (December 2004)
<tr><td><a href="#release3.0.1">3.0.1</a><td> (February 2004)
<tr><td><a href="#release3.0">3.0</a><td> (October 2003)
<tr><td><a href="#release2.4">2.4</a><td> (May 2002)
<tr><td><a href="#release2.3">2.3</a><td> (August 2001)
<tr><td><a href="#release2.2">2.2</a><td> (October 2000)
<tr><td><a href="#release2.1">2.1</a><td> (January 2000)
<tr><td><a href="#release2.0">2.0</a><td> (June 1999)
<tr><td><a href="#release1.2">1.2</a><td> (January 1999)
<tr><td><a href="#release1.1">1.1</a><td> (July 1998)
<tr><td><a href="#release1.0">1.0</a><td> (April 1998)
<tr><td><a href="#release0.9">0.9</a><td> (June 1997)
</table>

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<caption align=BOTTOM>
Number of lines of code of CGAL<br>
(using <a href="http://www.dwheeler.com/sloccount/"> David A. Wheeler's
'SLOCCount'</a>, restricted to the <code>include/CGAL/</code>
and <code>src/</code> directories).
</caption>
<tr><td><img src="images/release_history_sloccount.png" alt="Releases size graph">
</table>
<td width="10%">
</table>

<HR>
<h2 id="release4.7">Release 4.7 </h2>
<div>
  <p>Release date: September 2015 </p>

<!-- Installation (and general changes) -->
<!-- New packages -->
  <h3>Triangulated Surface Mesh Shortest Paths (new package)</h3>
  <ul>
    <li>
      The package provides methods for computing shortest path on
      triangulated surface meshes. Given a set of source points
      on the surface, this package provides a data structure that
      can efficiently provides the shortest path from any point on
      the surface to the sources points.
      There is no restriction on the genus or the number of connnected
      components of the mesh.
    </li>
  </ul>
<!-- Major and breaking changes -->
  <h3>Approximation of Ridges and Umbilics on Triangulated Surface Meshes</h3>
<ul>
<li> This package now supports any model of the concept <code>FaceGraph</code>.
<li> <b>Breaking change:</b> The package no longer support models of <code>TriangulatedSurfaceMesh</code> which are not at the same time model of the concept <code>FaceGraph</code>. 
</li>
</ul>
<!-- Arithmetic and Algebra -->
<!-- Combinatorial Algorithms -->
<!-- Geometry Kernels -->
<!-- Convex Hull Algorithms -->
<!-- Polygons -->
<!-- Cell Complexes and Polyhedra -->
<!-- Arrangements -->
  <h3>2D Arrangements</h3>
  <ul>
    <li>Introduced a new traits class, called
      <code>Arr_polycurve_traits_2&lt;SubcurveTraits&gt;</code>, which handles
      general piece-wise (polycurve) curves. The pieces do not necessarily
      have to be linear.</li>
    <li>Introduced two new concepts called
      <code>ArrangementApproximateTraits_2</code> and
      <code>ArrangementConstructXMonotoneCurveTraits_2</code>.
      <ul>
	<li>The existing <code>ArrangementLandmarkTraits_2</code> concept,
	  which has two requirements, now refines the two respective concepts
	  above.</li>
	<li>The template parameter of the exsting
	  <code>Arr_polyline_traits_2&lt;SegmentTraits&gt;</code> template must
	  be substituted with a traits class that is a model of
	  the <code>ArrangementConstructXMonotoneTraits_2</code> concept among
	  the other when <code>Arr_polyline_traits_2</code> is
	  instantiated.</li>
      </ul></li>
  </ul>
  <h3>2D Minkowski Sums</h3>
  <ul>
    <li>Added support for polygons with holes and optimized the construction
      of Minkowski sums.
    <ul>
      <li>Introduced an implementation of the "reduced convolution" method, a
	variant of the method described in "2D Minkowski Sum of Polygons Using
	Reduced Convolution" by Behar and Lien. The new method supports polygons
	with holes and in many cases out pergorms the implementation of the
	exsisting (full) convolution method.</li>
      <li>Introduced two new classes that decompose polygons into convex pieces
	(models of the <code>PolygonConvexDecomposition_2</code> concept) based
	on vertical decomposition and constrained Delaunay triangulation,
	respectively. These new models also support the convex decomposition of
	polygons with holes.</li>
    </ul></li>
  </ul>

<!-- Triangulations and Delaunay Triangulations -->
<!-- Voronoi Diagrams -->
<!-- Mesh Generation -->
  <h3>2D Conforming Triangulations and Meshes</h3>
  <ul>
    <li>
    Add an optimization method <code>CGAL::lloyd_optimize_mesh_2()</code> that implements
    the Lloyd (or Centroidal Voronoi Tesselation) optimization algorithm
    in a Constrained Delaunay Triangulation.
    For optimization, the triangulation data structure on which the mesher relies
    needs its <code>VertexBase</code> template parameter to be a model
    of the new concept <code>DelaunayMeshVertexBase_2</code>.
    </li>
  </ul>
<!-- Geometry Processing -->
  <h3>Point Set Processing and Surface Reconstruction from Point Sets</h3>
  <ul>
    <li>
    Add the function <code>CGAL::compute_vcm()</code> for computing the
    Voronoi Covariance Measure (VCM) of a point set. The output of this function
    can be used with the function <code>CGAL::vcm_is_on_feature_edge()</code>
    to determine whether a point is on or close to a feature edge. The former
    function is also internally used by <code>CGAL::vcm_estimate_normals()</code>
    to estimate the normals of a point set and it is particularly suited to point
    set with noise.
    </li>
  </ul>
<!-- Spatial Searching and Sorting -->
  <h3>Spatial Sorting</h3>
  <ul>
        <li>Add the possibility to sort points on a sphere along
            a space-filling curve using the functions
            <code>CGAL::hilbert_sort_on_sphere</code> and
            <code>CGAL::spatial_sort_on_sphere</code>.</li>
  </ul>
<!-- Geometric Optimization -->
<!-- Interpolation -->
<!-- Support Library -->
  <h3>Geometric Object Generators</h3>
  <ul>
    <li>Add new random generator of points in a 2D and 3D triangle and in a tetrahedron
        (<code>CGAL::Random_points_in_triangle_2</code>,
        <code>CGAL::Random_points_in_triangle_3</code>,
        <code>CGAL::Random_points_in_tetrahedron_3</code>).
    </li>
  </ul>


<!-- end of the div for 4.7 -->
</div>

<h2 id="release4.6.1">Release 4.6.1 </h2>
<div>
  <p>Release date: June 2015 </p>

  <p>This release only fixes bugs. See the list of fixed bugs on Github:</p>
  <p><a href="https://github.com/CGAL/cgal/issues?q=milestone%3A4.6.1+-label%3Ainvalid">
    https://github.com/CGAL/cgal/issues?q=milestone%3A4.6.1+-label%3Ainvalid
  </a></p>
</div>

<h2 id="release4.6">Release 4.6 </h2>
<div>
  <p>Release date: April 2015 </p>

<!-- Installation (and general changes) -->
  <h3>Installation</h3>
  <ul>
    <li>The required version of Boost is now 1.48 or higher.</li>
  </ul>
<!-- New packages -->
  <h3>2D Polyline Simplification (new package)</h3>
  <ul>
    <li>This package enables to simplify polylines with the guarantee
        that the topology of the polylines does not change. This can be
        done for a single polyline as well as for a set of polyline
        constraints in a constrained triangulation. The simplification
        can be controlled with cost and stop functions.</li>
  </ul>

  <h3>2D Generalized Barycentric Coordinates (new package)</h3>
  <ul>
    <li>This package offers an efficient and robust implementation of
        two-dimensional closed-form generalized barycentric coordinates
        defined for simple two-dimensional polygons.</li>
  </ul>

  <h3>Scale-Space Surface Reconstruction (new package)</h3>
  <ul>
    <li>This new package provides a class gathering a dedicated smoothing
        algorithm and some convenience functions to help the creation of
        a surface out of a point set using the 3D Alpha Shapes package.
        The particularity of this reconstruction pipeline is that the
        input point are in the output and no new points are created.
        Note that in the current version, the output is a triangle soup
        that is not necessarily a valid (manifold) polyhedral surface.
    </li>
  </ul>

  <h3>Surface Mesh (new package)</h3>
  <ul>
    <li>The surface mesh class provided by this package is an implementation
        of the halfedge data structure allowing to represent polyhedral surfaces.
        It is an alternative to the packages <code>CGAL::Polyhedron_3</code>
        and <code>CGAL::HalfedgeDS</code>. </li>
  </ul>

  <h3>dD Triangulation (new package)</h3>
  <ul>
    <li>This new package provides classes for manipulating triangulations
        in Euclidean spaces whose dimension can be specified at
        compile-time or at run-time. It also provides a class that
        represents Delaunay triangulations.</li>
  </ul>

<!-- Major and breaking changes -->
  <h3>dD Convex Hulls and Delaunay Triangulations</h3>
  <ul>
    <li>This package is deprecated and the new package Triangulation should be used instead.</li>
  </ul>
<!-- Arithmetic and Algebra -->
<!-- Combinatorial Algorithms -->
<!-- Geometry Kernels -->
  <h3>dD Geometry Kernel</h3>
  <ul>
    <li> It has been reported that the recently introduced <code>Epick_d</code>
      kernel may not work with Intel C++ Compiler prior to version 15.
      Documentation has been updated.</li>
  </ul>
<!-- Convex Hull Algorithms -->
  <h3>3D Convex Hulls</h3>
  <ul>
    <li>Add functions <code>halfspace_intersection_3</code> and
        <code>halfspace_intersection_with_constructions_3</code> to compute
        the intersection of halfspaces defining a closed polyhedron.</li>
    <li>Fix a bug introduced in CGAL 4.5 that can appear while computing
        the convex hull of coplanar points.</li>
    <li>Fix a robustness issue in <code>Convex_hull_traits_3</code>.
        This traits is used by default with the kernel
        <code>Exact_predicates_inexact_constructions_kernel</code>.</li>
    <li>The function <code>CGAL::convex_hull_incremental_3</code> is deprecated and
        the function <code>convex_hull_3</code> should be used instead.</li>
  </ul>
<!-- Polygons -->
<!-- Cell Complexes and Polyhedra -->
  <h3>Combinatorial Maps and Linear Cell Complex</h3>
  <ul>
    <li>Added <code>correct_invalid_attributes</code>,
      <code>set_automatic_attributes_management</code> and
      <code>are_attributes_automatically_managed</code> methods in
      <code>CombinatorialMap</code> concept. This allows high level
      operations to not update non void attributes during massive calls
      of these operations, but only after the end of their executions.
    </li>
  </ul>
<!-- Arrangements -->
<!-- Triangulations and Delaunay Triangulations -->
 <h3>2D Triangulations</h3>
  <ul>
    <li>The class <code>Constrained_triangulation_plus_2</code> now
        can handle polylines as constraints.</li>
    <li>As a consequence a <code>Constraint_id</code> has been introduced
        which replaces <code>pair&lt;Vertex_handle,Vertex_handle&gt;</code> as
        identifier of a constraint.
  </ul>
<!-- Voronoi Diagrams -->
<!-- Mesh Generation -->
  <h3>3D Mesh Generation</h3>
  <ul>
    <li>Add member functions <code>output_boundary_to_off</code> and
        <code>output_facets_in_complex_to_off</code>
        in the class <code>CGAL::Mesh_complex_3_in_triangulation_3</code>
        to export the boundary of a domain or a subdomain.</li>
  </ul>
<!-- Geometry Processing -->
<!-- Spatial Searching and Sorting -->
  <h3>3D Fast Intersection and Distance Computation</h3>
  <ul>
    <li>Add new constructors
    to <code>AABB_halfedge_graph_segment_primitive</code> and
    <code>AABB_face_graph_triangle_primitive</code> in order to be able to
    build primitives one by one.</li>
  </ul>
  <h3>Spatial Searching</h3>
  <ul>
    <li>
      Fixed a bug in <code>CGAL::Splitters.h</code> sliding midpoint rule,
      where degenerated point sets (e.g.,points on segment)
      caused the kd-tree to get linear.
    </li>
    <li>
      Improved performance of <code>Orthogonal_k_neighbor_search</code>.
      Note that VC 2013 does not
      compile <code>boost::container::deque</code> of Boost 1_55 and does
      hence have a workaround which does not have the improvement.
    </li>
    <li>
      <b>Breaking change:</b> The concept <code>OrthogonalDistance</code> has
      new function overloads for <code>min_distance_to_rectangle</code> and
      <code>max_distance_to_rectangle</code> with an additional reference
      parameter <code>std::vector</code>.
    </li>
    <li>
      <b>Breaking change:</b> The order of the points in the iterator range
      <code>[tree.begin(),tree.end()]</code> is not the order of
      insertion of the points into the tree.  This was not guaranteed before
      but might have been observed and exploited by users.
    </li>
    <li>
      Derived <code>kd_tree_leaf_node</code>
      and <code>kd_tree_internal_node</code> from <code>kd_tree_node</code>
      to save memory.
    </li>
  </ul>
<!-- Geometric Optimization -->
<!-- Interpolation -->
<!-- Support Library -->
  <h3>Geometric Object Generators</h3>
  <ul>
    <li>Add a new function <code>random_convex_hull_in_disc_2</code> that
        efficiently generates a random polygon as the convex hull of
        uniform random points chosen in a disc.</li>
  </ul>
<!-- end of the div for 4.6 -->
</div>

<h2 id="release4.5.2">Release 4.5.2</h2>
<div>
  <p>Release date: February 2015</p>

  <h3>General</h3>
  <ul>
    <li> Fix a bug that prevented the compilation with recent versions of
    Boost (>=1.56) when explicit conversions operators (from C++11) are
    supported. That prevented the compilation with Microsoft Visual Studio
    2013.
  </ul>
  <h3>3D Convex Hulls</h3>
  <ul>
    <li> Fix a non-robust predicate bug that was showing up when input
    points where lexicographically sorted.</li>
  </ul>
  <h3>3D Mesh Generation</h3>
  <ul>
    <li>Fix a bug in the sliver perturbation optimization method.  It could
      create some holes on the surface of the mesh.</li>
  </ul>
</div>

<h2 id="release4.5.1">Release 4.5.1 </h2>
<div>
  <p>Release date: December 2014 </p>

  <h3>3D Mesh Generation</h3>
  <ul>
    <li>Fix a bug in the sliver exudation preservation of boundaries. </li>
  </ul>
</div>

<h2 id="release4.5">Release 4.5 </h2>
<div>
  <p>Release date: October 2014 </p>

<!-- Installation (and general changes) -->
  <h3>Installation</h3>
  <ul>
    <li>Changes in the set of supported platforms:
      <ul>
        <li>The Microsoft Windows Visual C++ compiler 2008 (VC9) is no
          longer supported since CGAL-4.5.</li>
      </ul>
    </li>
    <li>Since CGAL version 4.0, Eigen was the recommended third-party
      library to use with <i>Planar Parameterization of Triangulated
      Surface Meshes</i>, <i>Surface Reconstruction from Point
      Sets</i>, <i>Approximation of Ridges and Umbilics on Triangulated
      Surface Meshes</i>, and <i>Estimation of Local Differential
      Properties of Point-Sampled Surfaces</i> packages. From CGAL
      version 4.5, Taucs, Blas and Lapack are no longer supported.
    </li>
    <li>CGAL is now compatible with the new CMake version 3.0.</li>
  </ul>

<!-- New packages -->
  <h3>Triangulated Surface Mesh Deformation (new package)</h3>
  <ul>
    <li> This package allows to deform a triangulated surface mesh
      under positional constraints of some of its vertices without
      requiring any additional structure other than the surface mesh itself.
      The methods provided implements an as-rigid-as-possible deformation.
      Note that the main class name has changed between the 4.5-beta1 and the 4.5
      releases to better match the CGAL naming conventions
      (from <code>CGAL::Deform_mesh</code> to <code>CGAL::Surface_mesh_deformation</code>).
    </li>
  </ul>

<!-- Major and breaking changes -->
  <h3>CGAL and the Boost Graph Library (major changes)</h3>
  <ul>
    <li>Cleanup of the <code>HalfedgeGraph</code> concept. In particular:
    <ul>
      <li>Introduction of the notion of <code>halfedge_descriptor</code> in
        the specialization of the
        class <code>boost::graph_traits</code>.</li>
      <li>Deprecation of <code>halfedge_graph_traits</code>.</li>
      <li>A model of <code>HalfedgeGraph</code> is considered as an
        undirected graph. Thus any call to <code>edges()</code> should be
        replaced by <code>halfedges()</code> and <code>num_edges()</code>
        now returns the number of (undirected) edges.
      <li><b>Breaking change:</b> <code>is_border_edge</code>
        and <code>is_border_halfedge</code> properties are removed.  The
        free functions <code>is_border()</code>
        and <code>is_border_edge()</code> should be used instead.</li>
      <li>Renaming of <code>HalfedgeGraph</code> specific free
        functions.</li>
    </ul>
    </li>
    <li>Introduction of the <code>FaceGraph</code> concept.</li>
    <li>Adaptation of the package <em>Triangulated Surface Mesh
      Simplification</em> and of the
      class <code>AABB_halfedge_graph_segment_primitive</code> from the
      package <em>3D Fast Intersection and Distance Computation</em> to
      the API change.</li>
    <li>Update of the package <em>Triangulated Surface Mesh
      Segmentation</em> and of the class
      <code>AABB_face_graph_triangle_primitive</code> from the
      package <em>3D Fast Intersection and Distance Computation</em> to
      accept model of the newly introduced concepts.</li>
    <li>Offer <em>Euler</em> operations as free functions for models of the
      graph concepts provided by CGAL.</li>
    <li>Specialization of <code>boost::graph_traits</code>
      for <code>OpenMesh::PolyMesh_ArrayKernelT</code> as proof of
      concept.  A <code>OpenMesh::PolyMesh_ArrayKernelT</code> becomes a
      model of the aforementioned concepts when including
      <code>CGAL/boost/graph/graph_traits_PolyMesh_ArrayKernelT.h</code>.</li>
  </ul>

<!-- Geometry Kernels -->
  <h3>dD Geometry Kernel</h3>
  <ul>
    <li> A new model <code>Epick_d</code> of the <code>Kernel_d</code>
      concept is introduced. It provides better performance through
      arithmetic filtering and specializations for fixed dimensions. It may
      not work with compilers as old as gcc-4.2, but was tested with
      gcc-4.4.</li>
  </ul>

<!-- Convex Hull Algorithms -->
  <h3>3D Convex Hulls</h3>
  <ul>
    <li> Clean up the documentation of the concepts</li>
  </ul>

<!-- Arrangements -->
  <h3>2D Arrangements</h3>
  <ul>
    <li>Fixed a bug in removing an unbounded curve (e.g., a ray) from
      an arrangement induced by unbounded curves.</li>
  </ul>

  <h3>2D Snap Rounding</h3>
  <ul>
    <li> Replaced use of private <code>kd_tree</code> with CGAL's
      official <code>Kd_tree</code> from <code>Spatial_searching</code>
      package; results in a small performance gain. Removed the
      private <code>kd_tree</code> package.
    </li>
  </ul>

<!-- Triangulations and Delaunay Triangulations -->
  <h3>3D Triangulations</h3>
  <ul>
    <li> Add an experimental parallel version of the Delaunay triangulation
      and the regular triangulation algorithms, which allows parallel
      insertion and removal of point ranges.</li>
  </ul>

<!-- Mesh Generation -->
  <h3>3D Mesh Generation</h3>
  <ul>
    <li>Add a new constructor for the
      class <code>Labeled_mesh_domain_3</code> which takes
      an <code>Iso_cuboid_3</code>.</li>
    <li>Add a new labeling function wrapper for meshing multi-domain.</li>
    <li>The meshing functionality in the Qt demos
      in <code>demo/Polyhedron/</code> and <code>demo/Mesh_3/</code> can
      now use the handling of 1d-features, that exists in CGAL since
      version 3.8.
    <li> Add an experimental parallel version of the 3D mesh refinement and
      mesh optimization methods.
    </li>
    <li>Add caching of circumcenters to
      <code>Regular_triangulation_cell_base_3</code>. The cache value is
      computed when <code>cell->circumcenter()</code>
      or <code>rt.dual(cell)</code> functions are called.
    </li>
  </ul>

<!-- Geometry Processing -->
  <h3>Point Set Processing and Surface Reconstruction from Point Sets</h3>
  <ul>
    <li>The former demo has been removed and is fully merge in the
    Polyhedron demo.</li>
  </ul>

  <h3>Point Set Processing</h3>
  <ul>
    <li>Workaround a bug in dijsktra shortest path of boost 1.54 by
      shipping and using the boost header from the 1.55 release. This
      header will be used only if you are using the version 1.54 of
      boost.
    </li>
  </ul>

  <h3>Triangulated Surface Mesh Simplification</h3>
  <ul>
    <li>
      <b>Breaking change:</b> Due to the cleanup of the concepts of the
      package <em>CGAL and the Boost Graph Library</em>, the named
      parameter <code>edge_is_border_map</code> has been removed, and the
      named parameter
      <code>edge_is_constrained_map</code> now expects a property map with
      an edge descriptor as key type (vs. halfedge descriptor before).
    </li>
    <li>Add some optimization in the code making the implementation faster
      (depending on the cost and the placement chosen). However, for an
      edge which collapse is not topologically valid, the vector of
      vertices of the link provided by its profile might contains
      duplicates, thus also breaking the orientation guarantee in the
      vector.  This must not be a problem for users as the edge is not
      collapsible anyway but if it is a absolute requirement for user
      defined cost/placement, defining the
      macro <code>CGAL_SMS_EDGE_PROFILE_ALWAYS_NEED_UNIQUE_VERTEX_IN_LINK</code>
      will restore the former behavior.
    </li>
  </ul>

<!-- Spatial Searching and Sorting -->
  <h3>dD Spatial Searching</h3>
  <ul>
    <li> Added methods <code>reserve(size_t size)</code> and <code>size_t
      capacity()</code> to class <code>Kd_tree</code> to allocate memory
      to store <code>size</code> points and to report that number (STL
      compliance).
    </li>
  </ul>

<!-- Support Library -->
  <h3>STL Extensions for CGAL</h3>
  <ul>
    <li> Add <code>Compact_container::operator[]</code>, allowing a direct
      access to the ith element of a compact container.</li>
    <li> Add <code>Concurrent_compact_container</code>, a compact container
      which allows concurrent insertion and removal.</li>
  </ul>

<!-- end of the div for 4.5 -->
</div>

<h2 id="release4.4">Release 4.4 </h2>
<div>
  <p>Release date: April 2014 </p>
  <h3>Installation</h3>
  <ul>
    <li>Additional supported platforms:
      <ul>
        <li>The Apple Clang compiler version 5.0 is now supported on
          OS X Mavericks.</li>
        <li>The Microsoft Windows Visual C++ compiler 2013 (VC12) is now
          supported.</li>
      </ul>
    </li>
  </ul>
  <h3>Triangulated Surface Mesh Segmentation (new package)</h3>
  <ul>
    <li> This package implements the segmentation of triangulated surface meshes
         based on the Shape Diameter Function (SDF). In addition, it also provides
         functions to generate segmentations based on a user defined alternative
         to the SDF.
    </li>
  </ul>


  <h3>Number Types</h3>
  <ul>
    <li> A new class <code>CGAL::Mpzf</code> is introduced on some platforms
      for exact ring operations. It is used to improve the speed of the
      evaluation of predicates in degenerate situations.</li>
  </ul>

  <h3>2D and 3D Geometry Kernel </h3>
  <ul>
    <li> Fix a bug introduced in CGAL 4.3 when computing the intersection
         of two 3D triangles.</li>
  </ul>

  <h3>2D Polygon Partitioning</h3>
  <ul>
    <li>Bug fix to make the partition algorithms working with a Lazy kernel such as
        <code>Exact_predicates_exact_constructions_kernel</code>.
    </li>
  </ul>

  <h3>2D Regularized Boolean Set-Operations</h3>
  <ul>
    <li>Fix two memory leaks in
      <code>CGAL::General_polygon_set_2</code>.
    </li>
  </ul>

  <h3>Combinatorial Maps and Linear Cell Complex</h3>
  <ul>
    <li> <code>null_dart_handle</code> is no longer a static data member in
      the <code>CombinatorialMap</code> concept. This implies to move the
      following methods of <code>Dart</code> concept
      into <code>CombinatorialMap</code>
      concept: <code>is_free</code>, <code>highest_nonfree_dimension</code>,
      <code>opposite</code> and <code>other_extremity</code>. We also
      transform the static methods <code>vertex_attribute</code>
      and <code>point</code> of <code>Linear_cell_complex</code> class into
      non static methods. You can define the CGAL_CMAP_DEPRECATED macro to
      keep the old behavior.
    </li>
  </ul>

  <h3>2D Arrangements</h3>
  <ul>
    <li> Revise the API of <b>polylines</b>. In particular,
      <i>construction</i> is now done using functors
      and <i>iteration</i> is possible only on the segments of a
      polyline.
    <li>Fix a bug in the <i>Landmark</i> point-location strategy.</li>
  </ul>

  <h3>2D Snap Rounding</h3>
  <ul>
    <li>Fix a memory leak</li>
  </ul>

  <h3>2D Triangulations</h3>
  <ul>
    <li>Add different overloads of the function <code>insert_constraints</code>
        that inserts a range of points and segments, or a range of segments.
        These functions uses the spatial sorting in order to speed
        up the time needed for the insertion.
    </li>
  </ul>

  <h3>3D Periodic Triangulations</h3>
  <ul>
    <li>Add a method to locate point with inexact predicates.
    </li>
    <li>Rename Periodic_3_triangulation_traits_3 Periodic_3_Delaunay_triangulation_traits_3.
    </li>
    <li>Rename the concept Periodic_3TriangulationTraits_3 Periodic_3DelaunayTriangulationTraits_3.
    </li>
    <li>Create Periodic_3_triangulation_traits_3 and the concept Periodic_3TriangulationTraits_3. 
    </li>
  </ul>

  <h3>3D Alpha Shapes</h3>
  <ul>
    <li> Add member functions in <code>CGAL::Alpha_shape_3</code> to give
         access to the alpha status of edges and facets
         (<code>get_alpha_status())</code>.</li>
    <li> Add another filtration method
          (<code>filtration_with_alpha_values()</code>) that reports the
          alpha value at which each face appears in the filtration.</li>
  </ul>

  <h3>3D Mesh Generation</h3>
  <ul>
    <li>Fix the access to functions <code>number_of_facets</code>
	and <code>number_of_cells</code> in
	<code>Mesh_complex_3_in_triangulation_3</code>.
    </li>
    <li>Change the internal API of the sliver perturber, to make possible
	for developers to optimize another criterion than the (default)
	minimal dihedral angle.  Developers can also define a new
	perturbation vector (for angles we had gradient of squared
	circumradius, gradient of volume, gradient of minimal dihedral
	angle, and random) which is better suitable to optimize their
	criterion.
    </li>
    <li>Improve the use of cache values in <code>Mesh_cell_base_3</code> to
          (re)compute circumcenters and sliver criterion values only when
          needed.
    </li>
  </ul>

  <h3>Triangulated Surface Mesh Simplification</h3>
  <ul>
    <li>Fix a bug in the way edges can be marked as non-removable by adding
        a named-parameter <code>edge_is_constrained_map</code> to the function
        <code>edge_collapse</code></li>
  </ul>

  <h3>dD Spatial Searching</h3>
  <ul>
    <li>Fix a documentation bug: The property map passed as template
      parameter to the classes
      <code>Search_traits_adapter</code> and <code>Distance_adapter</code>
      must be a lvalue property map. To avoid incorrect usage, a static
      assertion has been added in the CGAL code to prevent the user from
      instantiating these classes with an incorrect property map type.</li>
  </ul>

 <h3>CGAL ipelets</h3>
  <ul>
    <li> Better description of the demo ipelets in the user manual     </li>
    <li> New ipelet for pencils of circles</li>
    <li> New ipelet for hyperbolic geometry in Poincaré model</li>
    <li> The generator ipelet now generates point in a selected zone</li>
    <li> Hilbert sort ipelet implements two policies</li>
  </ul>
</div>

<h2 id="release4.3">Release 4.3 </h2>
<div>
  <p> Release date: October 2013 </p>

  <h3>The CGAL Manual</h3>
  <ul>
    <li>The documentation of CGAL is now generated with Doxygen.</li>
  </ul>

  <h3>2D Periodic Triangulations (new package)</h3>
  <ul>
    <li> This package allows to build and handle triangulations of point
      sets in the two dimensional flat torus. Triangulations are built
      incrementally and can be modified by insertion or removal of
      vertices. They offer point location facilities.  The package provides
      Delaunay triangulations and offers nearest neighbor queries and
      primitives to build the dual Voronoi diagrams.
    </li>
  </ul>

  <h3>API Changes</h3>
      <h4>2D and 3D Geometry Kernel </h4>
      <ul>
        <li> The intersection functions and functors used to return
          a <code>CGAL::Object</code> in order to deal with the different
          possible return types. However, depending on the arguments it is
          possible to reduce the possible return types to a small set. For
          this reason and to take advantage of the type safety, we decided
          to use <code>boost::variant</code> instead
          of <code>CGAL::Object</code>.  The <code>result_of</code>
          protocol is now even more useful to determine the return type of
          the intersection functions and functors. The change should be
          relatively transparent to the user thanks to the implicit
          constructor added to <code>CGAL::Object</code>. However, it is
          recommended to upgrade your code.  The previous behavior can be
          restored by defining the
          macro <code>CGAL_INTERSECTION_VERSION</code> to 1.
        </li>
      </ul>
      <h4>2D Arrangements</h4>
      <ul>
        <li> The type of the result of point location queries changed to
	  <code>boost::variant</code> (from <code>CGAL::Object</code>).
	  For convenience, the previous behavior can be restored by defining
	  the macro <code>CGAL_ARR_POINT_LOCATION_VERSION</code> to 1.
	<li> Introduced an optimization for operations on large and dense
	  arrangements.
        </li>
      </ul>
      <h4>3D Fast Intersection and Distance Computation</h4>
      <ul>
        <li>Following the intersection API
          change, <code>Object_and_primitive_id</code> has been replaced by
          a template class
          <code>Intersection_and_primitive_id&lt;Query&gt;</code> to determine
          the type depending on the query object type.
        </li>
      </ul>
      <h4>CGAL and Boost Property Maps</h4>
      <ul>
        <li>The <code>key_type</code> of the property maps provided by CGAL
          used to be an iterator. In order to be more easily re-used,
          the <code>key_type</code> has been changed to be
          the <code>value_type</code> of the iterator.  The packages that
          have been updated to match these changes are <b>Point Set
          Processing</b> and <b>Surface Reconstruction from Point Sets</b>.
          However, for most users this change should be transparent if the
          default property maps were used.  For convenience, the former
          behavior can be enabled by defining the
          macro <code>CGAL_USE_PROPERTY_MAPS_API_V1</code>.
    </li>
  </ul>

  <h3>Algebraic Foundations</h3>
  <ul>
    <li>For convenience, add an overload of <code>make_rational()</code>
    taking a pair of numbers.</li>
  </ul>

  <h3>2D and 3D Geometry Kernel </h3>
  <ul>
    <li>A <code>Iso_rectangle_2</code> can now be constructed from
      a <code>Bbox_2</code> and an <code>Iso_cuboid_3</code> from
      a <code>Bbox_3</code>. </li>
    <li> The implementation of <code>CGAL::Object</code> has been updated
      and now uses <code>boost::shared_ptr</code>
      and <code>boost::any</code>. This implementation is faster.
    </li>
    <li>Add to <code>Bbox_2</code> and <code>Bbox_3</code>
      a <code>+=</code> operator as well as free functions to get the
      bounding box of a range of geometric objects.
    </li>
  </ul>

  <h3>Combinatorial Maps</h3>
  <ul>
    <li>Two bug fixes: do not use the 2 least significant bits for cell
      attribute without dart support; share the mark when copying a
      CMap_cell_iterator.</li>
    <li>Add a constructor taking a given combinatorial map as argument,
      possibly with different dimension and/or different attributes. This
      allows to transform a combinatorial map.</li>
    <li>Add operator= and swap method.</li>
    <li>Add dynamic onmerge/onsplit functions that can be associated
      dynamically to i-attributes and which are automatically called when
      i-cells are split/merged.</li>
    <li>Add a function allowing to reverse the orientation of a
      combinatorial map, and another one to reverse one connected component
      of a combinatorial map.</li>
  </ul>

  <h3>3D Boolean Operations on Nef Polyhedra</h3>
  <ul>
    <li>Bug-fix in IO when using <code>Lazy_exact_nt</code> as number type
      or <code>Exact_predicates_exact_constructions_kernel</code> as
      kernel.</li>
  </ul>

  <h3>2D Triangulations</h3>
  <ul>
    <li>Extend the concept <code>TriangulationDataStructure_2</code> to
      require a more general <code>copy_tds</code> function that allows a
      copy between TDS of different types. The CGAL model has been
      updated.</li>
    <li>Add a way to efficiently insert a range of points with information
      into the 2D constrained Delaunay triangulations.
  </ul>

  <h3>3D Triangulations</h3>
  <ul>
    <li>Extend the concept <code>TriangulationDataStructure_3</code> to
      require a more general <code>copy_tds</code> function that allows a
      copy between TDS of different types. The CGAL model has been
      updated.</li>
    <li>Add an advanced function to set the infinite vertex of the
      triangulation for low level operations</li>
    <li>Fix a bug in the function inserting a range of points with info
      when the <code>Fast_location</code> tag is used</li>
  </ul>

  <h3>2D Segment Delaunay Graph</h3>
  <ul>
    <li>Add functions <code>insert_points</code>
      and <code>insert_segments</code> to insert a range of points and
      segments. These functions uses the spatial sorting in order to speed
      up the time needed for the insertion. The
      function <code>insert(Input_iterator first, Input_iterator beyond,
      Tag_true)</code> has been updated to dispatch the input when possible
      to these functions.
    </li>
  </ul>

  <h3>2D Apollonius Graphs</h3>
  <ul>
    <li>Modified insertion algorithm so that the code can handle
      pseudo-circles as well.</li>
    <li>Updated implementation of the vertex conflict predicate by a
      faster version.</li>
  </ul>

  <h3>3D Mesh Generation</h3>
  <ul>
    <li>Speed-up <code>Mesh_3</code> and in particular the global
      optimizers (Lloyd and ODT) by introducing a
      parameter <code>do_freeze</code> to prevent from moving vertices
      which would move of very small displacements.</li>
    <li> Introduce new data structures and options for speed-up and
      compacity. Note that <code>Compact_mesh_cell_base_3</code> and
      <code>Mesh_vertex_base_3</code> are now our favoured implementations
      of the concepts MeshCellBase_3 and MeshVertexBase_3.
    </li>
    <li>Introduce a new constructor
      for <code>Polyhedral_mesh_domain_3</code> that takes a bounding
      polyhedron to be meshed along with a polyhedral surface entirely
      included in it.  This allows the user to mesh a polyhedral domain
      with internal surface(s) which can be non-watertight and even
      non-manifold.
    </li>
    <li> Several documentation bug fixes.</li>
    <li> Provide the ability to plug in custom cell_base/vertex_base
      classes into the Mesh_triangulation_3 class. </li>
  </ul>

  <h3>Triangulated Surface Mesh Simplification</h3>
  <ul>
    <li>Fix a segmentation fault that was happening when some edges of length 0
        were in the input mesh.</li>
  </ul>
  <h3>3D Fast Intersection and Distance Computation</h3>
  <ul>
    <li>Following the intersection API
      change, <code>Object_and_primitive_id</code> has been replaced by a
      template class
      <code>Intersection_and_primitive_id&lt;Query&gt;</code> to determine
      the type depending on the query object type.
    </li>
    <li>Introduce the
      class <code>AABB_halfedge_graph_segment_primitive</code>, which
      replaces the class <code>AABB_polyhedron_segment_primitive</code>
      (which is now deprecated).  The new class is more general and can be
      used with any model of <code>HalfedgeGraph</code>.</li>
    <li>Introduce the class <code>AABB_face_graph_triangle_primitive</code>
      which replaces the
      class <code>AABB_polyhedron_triangle_primitive</code> (which is now
      deprecated).</li>
    <li>Document the classes <code>AABB_segment_primitive</code>
      and <code>AABB_triangle_primitive</code> that were already used in
      some examples.</li>
    <li>Add a generic primitive class <code>AABB_primitive</code> that
      allows to define a primitive type by defining only two property
      maps.</li>
    <li>Introduce a new concept of
      primitive <code>AABBPrimitiveWithSharedData</code>. It allows to have
      some data shared between the primitives stored in
      a <code>AABB_tree</code>.  With this you can, for example have a
      primitive wrapping an integer which refers to the position of a
      geometric object in a <code>std::vector</code>.  Only one reference
      to this vector will be stored in the traits of the tree.  The
      concept <code>AABBTraits</code>, its model <code>AABB_traits</code>
      and the class <code>AABB_tree</code> have been updated accordingly.
      However, everything is backward compatible.</li>
    <li> Fix a memory leak in the destructor of the
    class <code>AABB-tree</code></li>
  </ul>

  <h3>STL Extensions for CGAL</h3>
  <ul>
    <li>Add to <code>Dispatch_output_iterator</code>
      and <code>Dispatch_or_drop_output_iterator</code> an operator to
      accept and dispatch a tuple of values.
    </li>
  </ul>

  <h3>Concurrency in CGAL</h3>
  <ul>
    <li>Add a <code>FindTBB</code> CMake module so that one can easily link
      with TBB to write shared-memory parallel code.</li>
    <li>Introduce two new tags: Sequential_tag and Parallel_tag</li>
  </ul>
</div>

<h2 id="release4.2">Release 4.2 </h2>
<div>
  <p> Release date: March 2013 </p>

  <h3>Installation</h3>
  <ul>
    <li>Additional supported platforms:
      <ul>
        <li>The Microsoft Windows Visual C++ compiler 2012 (VC11) is now
        supported.</li>
      </ul>
    </li>
    <li>With Microsoft Visual C++ (all supported versions), the compiler
      flags <code>/bigobj</code> and <code>/wd4503</code> are added by CGAL
      CMake scripts.
    </li>
    <li>This is the last release whose "<tt>UseCGAL.cmake</tt>" file (if
      using CGAL in a CMake build environment) contains the line
<pre>
  link_libraries(${CGAL_LIBRARIES_DIR} ${CGAL_3RD_PARTY_LIBRARIES_DIRS})
</pre>
      as this is a deprecated CMake command. The correct way to link with
      CGAL's libraries (as for required 3rd party libraries) is to use
      '<code>target_link_libraries</code>' which specifies for each build
      target which libraries should be linked. The following serves as
      example:
<pre>
  find_package(CGAL)
  include(${CGAL_USE_FILE})
  add_executable(myexe main.cpp)
  target_link_libraries(myexe ${CGAL_LIBRARIES}
                              ${CGAL_3RD_PARTY_LIBRARIES})
</pre>
      We also expect further changes in CGAL's CMake setup (change of
      variable names, consistency of filename and output, removing
      essential libraries, building executables, removal of
      '<code>${CGAL_3RD_PARTY_LIBRARIES}</code>').
    </li>
  </ul>

  <h3>2D Arrangements</h3>
  <ul>
    <li> Enhanced the 2D-arrangements demonstration program and ported it
      to Qt4. The new demonstration program makes use of the CGAL Graphics
      View framework, in which the 2D primitives are individually
      represented as objects in a scene. (The implementations of several
      demos in CGAL already make use of this framework.) This project was
      carried out as part of the 2012 Google Summer of Code program.</li>
    <li>Fixed a bug in the Walk-Along-A-Line point location strategy for
      arrangements induced by unbounded curves.</li>
  </ul>

  <h3>2D Circular Geometry Kernel</h3>
  <ul>
    <li>Fix the intersection type computed when intersecting two identical circles.</li>
    <li>Forward correctly the result type of the linear kernel functors</li>
  </ul>

  <h3>2D Triangulations</h3>
  <ul>
    <li> Add mechanism to avoid call stack overflow
    in <code>Delaunay_triangulation_2</code>
    and <code>Constrained_Delaunay_triangulation_2</code>.
    <li> Add a constructor for <code>Regular_triangulation_2</code>
    and <code>Delaunay_triangulation_2</code> from a range of points or a
    range of points with info.
  </ul>

  <h3>2D Voronoi Diagram Adaptor</h3>
  <ul>
    <li> Bug-fix: Add ccb() method in face type as documented.
  </ul>

  <h3>3D Minkowski Sum of Polyhedra</h3>
  <ul>
    <li> Fix a memory leak.
  </ul>

  <h3>3D Fast Intersection and Distance Computation</h3>
  <ul>
    <li> Update requirements of the concepts <code>AABBTraits</code>
    and <code>AABBGeomTraits</code> to match the implementation of the
    package.
  </ul>

  <h3>Generator</h3>
  <ul>
    <li> Addition of the <code>Combination_enumerator</code>
  </ul>

  <h3>STL Extensions</h3>
  <ul>
    <li>Introduction of <code>CGAL::cpp11::result_of</code> as an alias to
      the tr1 implementation from boost of the <code>result_of</code>
      mechanism.  When all compilers supported by CGAL will have a Standard
      compliant implemention of the C++11 <code>decltype</code> feature, it
      will become an alias to
      <code>std::result_of</code>.
    </li>
  </ul>

  <h3>Surface Reconstruction from Point Sets</h3>
  <ul>
    <li> Performance improvements and addition of an option to better
    reconstruct undersampled zones. The poisson reconstruction plugin
    of the Polyhedron demo has an option to switch it on.
  </ul>
</div>


<h2 id="release4.1">Release 4.1 </h2>
<div>
  <p> Release date: October 2012</p>

  <h3>Installation</h3>
  <ul>
    <li>Additional supported platforms:
      <ul>
        <li>The Apple Clang compiler versions 3.1 and 3.2 are now supported on
          Mac OS X.</li>
      </ul>
    </li>
    <li>Improved configuration for essential and optional external third party software</li>
    <li>Added more general script to create CMakeLists.txt files: <tt>cgal_create_CMakeLists</tt></li>
    <li>Availability tests for C++11 features are now performed with the help of <a href="http://www.boost.org/libs/config">Boost.Config</a>. A Boost version of 1.40.0 or higher is needed to use C++11 features.</li>
  </ul>

  <h3>2D Arrangement</h3>
  <ul>
    <li>Improved the implementation of the incremental randomized
      trapezoidal decomposition point-location strategy. The new
      implementation enables point location in unbounded arrangements. It
      constructs a search structure of guaranteed linear size with
      guaranteed logarithmic query time.
    </li>
  </ul>

  <h3>2D Convex Hulls and Extreme Points </h3>
  <ul>
    <li>Speed up the preprocessing stage of the Akl-Toussaint implementation (used by the free function <code>convex_hull_2</code> when forward iterators are provided as input).</li>
  </ul>

  <h3>Combinatorial Maps</h3>
  <ul>
    <li>Minor bugfix; replace some functors by methods.</li>
  </ul>

  <h3>Linear Cell Complex</h3>
  <ul>
    <li>Improve the demo: add a widget showing all the volumes and an operation to create a Menger sponge.</li>
  </ul>

  <h3>Kernels</h3>
  <ul>
    <li>All Kernel functors now support the result_of protocol.</li>
  </ul>

  <h3>STL_Extensions for CGAL</h3>
  <ul>
    <li>The namespace <code>cpp0x</code> has been renamed <code>cpp11</code>. The old name is still available for backward compatibility.</li>
  </ul>

</div>

<h2 id="release4.0.2">Release 4.0.2</h2>
<DIV>
<p>Release date: Jul 2012</p>

<p>
This is a bug fix release. It fixes a bug in
the <code>CMakeLists.txt</code> for CGAL-4.0.1, that prevented even
building the libraries.
</p>

</div>

<h2 id="release4.0.1">Release 4.0.1</h2>

<DIV>
<p>Release date: Jul 2012</p>

<p>
This is a bug fix release. Apart various minor fixes in the documentation,
the following has been changed since CGAL-4.0:</p>

<h3> 2D Voronoi Diagram Adaptor (re-added)</h3>
<ul>
  <li>The package <em>2D Voronoi Diagram Adaptor</em> was temporarily
  removed from the CGAL distribution because of license issues. That
  package is now back into CGAL.
  </li>
</ul>

<h3>2D and 3D Geometry Kernel </h3>
<ul>
  <li>Fix a bug in the <code>Segment_3-Triangle_3</code> intersection function in the case the segment is collinear with a triangle edge.</li>
  <li>Fix a bug in the <code>Projection_traits_.._3</code> class in the case a segment was parallel to the x-axis.</li>
</ul>

<h3>Algebraic Kernel</h3>
<ul>
  <li>Avoid the linking error "duplicate symbols" when two compilation units
    using the algebraic kernel are linked.</li>
</ul>

<h3>3D Boolean Operations on Nef Polygons Embedded on the Sphere</h3>
<ul>
<li>Fix a memory leak due to the usage of an internal mechanism that has
  been replaced by <code>boost::any</code>. This also influences the
  packages 2D Boolean Operations on Nef Polygons, 3D Boolean Operations on
  Nef Polyhedra, Convex Decomposition of Polyhedra, and 3D Minkowski Sum of
  Polyhedra.</li>
</ul>

<h3>2D Arrangement</h3>
<ul>
<li>Fix several memory leaks.</li>
</ul>

<h3>2D Mesh Generation</h3>
<ul>
  <li>Fix a compilation error in the
  header <code>&lt;CGAL/Mesh_2/Do_not_refine_edges.h&gt;</code> when g++
  version 4.7 is used.</li>
</ul>

<h3>Surface Mesh Generation and 3D Mesh Generation</h3>
<ul>
  <li>Fix an important bug in the <code>CGAL_ImageIO</code> library, that
  could lead to wrong result when meshing from a 3D image.</li>
  <li>Fix the compilation of the demo in <code>demo/Surface_mesher</code>,
  when Boost version 1.48 or 1.49 is used.</li>
</ul>

<h3>Surface Mesh Parameterization</h3>
<ul>
<li>Fix a memory leak.</li>
<li>Fix a compatibility issue with Eigen-3.1 of <code>Eigen_solver_traits</code>. This fix also affects the usage of
that class in the package <i>Surface Reconstruction from Point Sets</i>.</li>
</ul>

</DIV>

<h2 id="release4.0">Release 4.0 </h2>
<DIV>
<p> Release date: March 2012</p>

<p>
CGAL 4.0 offers the following improvements and new functionality :  </p>

<h3>License Changes</h3>
  <p>The whole CGAL-3.x series was released under a combination of LGPLv2 (for
  the foundations of CGAL), and QPL (for the high-level packages). QPL was
  the former license of the graphical toolkit Qt, but that license is not
  supported by any major free software project. Furthermore, the terms of
  the LGPLv2 license are ambiguous for a library of C++ templates, like
  CGAL.</p>

  <p>The CGAL project, driven by the CGAL Editorial Board, has decided to
  change the license scheme of CGAL. We increased the major number
  of the CGAL version to '4' in order to reflect this license change.
  The CGAL-4.x series is released under:</p>
  <ul>
    <li>LGPLv3+ (that is LGPL <em>"either version 3 of the License, or (at your
    option) any later version"</em>), for the foundations of CGAL, instead
    of LGPLv2,</li>
    <li>GPLv3+ for the high-level packages, instead of QPL.</li>
  </ul>

<h3>General</h3>
<ul>
  <li>On Windows, CGAL libraries are now built by default as shared
      libraries (also called DLL). To run applications that use .dll files
      of CGAL, you must either copy the .dll files into the directory of
      the application, or add the path of the directory that contains those
      .dll files into the PATH environment variable.
  </li>
  <li>On Windows, the CMake scripts of CGAL now search for shared version
      of the Boost libraries. You must ensure that the .dll files of Boost are
      found by the dynamic linker.  You can, for example, add the path to
      the Boost .dll files to the PATH environment variable.
  </li>
  <li>On Windows, CMake version 2.8.6 or higher is now required.
  </li>
  <li>Eigen version 3.1 or later is now the recommended third party library to use
      in  <i>Planar Parameterization of Triangulated Surface Meshes</i>,
      <i>Surface Reconstruction from Point Sets</i>,
      <i>Approximation of Ridges and Umbilics on Triangulated Surface Meshes</i>, and
      <i>Estimation of Local Differential Properties of Point-Sampled Surfaces</i>
      packages. If you use Eigen you no longer need Taucs, Lapack or Blas to use those
      packages (and any other in CGAL).
  </li>
</ul>


<h3>Linear Cell Complex (new package)</h3>
<ul>
  <li>This package implements linear cell complexes, objects in
    d-dimension  with linear geometry. The combinatorial part of
    objects is described by a combinatorial map, representing all the
    cells of the object plus the incidence and adjacency relations
    between cells. Geometry is added to combinatorial maps simply by
    associating a point to each vertex of the map.  This data
    structure can be seen as the generalization in dD of the
    <code>Polyhedron_3</code>.</li>
</ul>

<h3> 2D Voronoi Diagram Adaptor (temporarily removed)</h3>
<ul>
<li>  As the copyright holder of this package has not granted
  the right to switch from QPL to GPL, this package is
  removed from the distribution.

  Note that it is "only" an adapter, that is the functionality
  of point/segment/disk Voronoi diagram is offered through
  the Delaunay triangulation, segment Delaunay graph,
  and Apollonius graph.</li>
</ul>

<h3>AABB Tree</h3>
<ul>
  <li>Document constness of member functions of the <code>AABB_tree</code> class.</li>
  <li>The class <code>AABB_tree</code> is now guaranteed to be read-only thread-safe. As usual in CGAL,
      this small overhead introduced for thread-safety can be deactivated by defining <code>CGAL_HAS_NO_THREADS</code>.</li>
</ul>

<h3>2D Alpha Shapes</h3>
<ul>
  <li>Add an extra template parameter to the class <code>Alpha_shape_2</code> that allows a certified construction using
      a traits class with exact predicates and inexact constructions.</li>
  <li>An object of type <code>Alpha_shape_2</code> can now be constructed from a triangulation.</li>

</ul>

<h3>3D Alpha Shapes</h3>
<ul>
  <li>Add an extra template parameter to the class <code>Alpha_shape_3</code> that allows a certified construction using
      a traits class with exact predicates and inexact constructions.</li>
</ul>

<h3>Geometric Object Generators</h3>
<ul>
  <li> <code>Random_points_in_iso_box_d</code> (deprecated since 3.8) has been
  removed. Use <code>Random_points_in_cube_d</code> instead.
</ul>

<h3>Linear and Quadratic Programming Solver</h3>
<ul>
<li>Minor bugfix.</li>
</ul>

<h3>Spatial Searching</h3>
<ul>
  <li>The const-correctness of this package have been worked out. The transition for users should be smooth in
  general, however adding few const in user code might be needed in some cases.
  </li>
  <li>The class <code>Kd_tree</code> is now guaranteed to be read-only thread-safe. As usual in CGAL,
      this small overhead introduced for thread-safety can be deactivated by defining <code>CGAL_HAS_NO_THREADS</code>.</li>
  <li>Bug-fix in <code>Orthogonal_incremental_neighbor_search</code> and <code>Incremental_neighbor_search</code> classes. Several calls to <code>begin()</code>
      now allow to make several nearest neighbor search queries independently.</li>
</ul>

<h3>STL Extension</h3>
<ul>
  <li><code>CGAL::copy_n</code> is now deprecated for <code>CGAL::cpp0x::copy_n</code> which uses <code>std::copy_n</code>, if available on the platform.</li>
  <li><code>CGAL::successor</code> and <code>CGAL::predecessor</code> are now deprecated for <code>CGAL::cpp0x::next</code> and <code>CGAL::cpp0x::prev</code>. These functions
  use the standard versions if available on the platform. Otherwise, <code>boost::next</code> and <code>boost::prior</code> are used.</li>
</ul>

<h3>Triangulation_2</h3>
<ul>
  <li> Fix a thread-safety issue in <code>Delaunay_triangulation_2</code> remove functions.  As usual in CGAL,
      the small overhead introduced for thread-safety can be deactivated by defining <code>CGAL_HAS_NO_THREADS</code>.</li>
  <li> Add extraction operator for the class <code>Constrained_triangulation_2</code> (and thus to all inheriting classes).</li>
</ul>

</div>

<h2 id="release3.9">Release 3.9 </h2>
<DIV>
<p> Release date: September 2011</p>

<p>
CGAL 3.9 offers the following improvements and new functionality :  </p>

<h3>General</h3>
<ul>
  <li>The class <code>Root_of_2</code> is now deprecated. It is recommended to use the class <code>Sqrt_extension</code> instead.</li>
  <li>The class <code>Sqrt_extension</code> is now used everywhere in CGAL where an algebraic number of degree 2 is needed.
      This change has been done in the <code>Root_of_traits</code> mechanism (indirectly packages 2D Circular kernel and 3D Spherical kernel)
      and the packages 2D Segment Delaunay Graphs and 2D Arrangements.</li>
  <li>Various fixes in the manual.</li>
</ul>

<h3>Combinatorial Maps (new package)</h3>
<ul>
  <li>This package provides a new combinatorial data structure allowing to describe any orientable subdivided object whatever its dimension.
  It describes all cells of the subdivision and all the incidence and adjacency relations between these cells.
  For example it allows to describe a 3D object subdivided in vertices, edges, faces and volumes.
  This data structure can be seen as the generalization in dD of the halfedge data structure.</li>
</ul>

<h3>3D Convex Hull (major performance improvement)</h3>
<ul>
      <li>The quickhull implementation of CGAL (<code>CGAL::convex_hull_3</code>)
          has been worked out to provide very better performances.</li>
      <li>The function <code>CGAL::convex_hull_3</code> no longer computes the plane
          equations of the facets of the output polyhedron. However an example is
          provided to show how to compute them easily.</li>
      <li>A global function <code>convex_hull_3_to_polyhedron_3</code> is now provided to extract
      the convex hull of a 3D points set from a triangulation of these points.</li>
</ul>

<h3>dD Spatial Searching (major new feature added)</h3>
<ul>
      <li>A traits-class and distance adapter that together with a point property map,
       allow to make nearest neighbor queries on keys instead of points have been added.</li>
      <li>Few bug fixes in the documentation have revealed some inconsistencies
      that have been corrected. Two traits class concept are now documented (<code>RangeSearchTraits</code>
      and <code>SearchTraits</code>). Most other changes concerns only classes documented as advanced.
      One issue that user can encounter is due to an additional requirement on the nested
      class <code>Construct_cartesian_const_iterator_d</code> defined in the concept SearchTraits that must
      provide a nested type <code>result_type</code>.</li>
</ul>

<h3>Spatial Sorting  (major new feature added)</h3>
<ul>
      <li>General dimension is now supported.</li>
      <li>Hilbert sorting admits now two policies: splitting at
      median or at middle (see user manual).</li>
      <li>Using a property map, sorting on keys instead of points is now easier</li>
</ul>

<h3>dD Kernel</h3>
<ul>
      <li>The d-dimensional kernel concept and models have been modified
          to additionally provide two new functors <code>Less_coordinate_d</code> and <code>Point_dimension_d</code>.</li>
</ul>

<h3>2D Arrangements</h3>
<ul>
      <li>A new geometry-traits class that handles rational arcs, namely
	<code>Arr_rational_function_traits_2</code>, has been introduced.
	It replaced an old traits class, which handled the same family of
	curves, but it was less efficient. The new traits exploits CGAL
	algebraic kernels and polynomials, which were not available at
	the time the old traits class was developed.</li>
      <li>A new geometry traits concept called
	<code>ArrangementOpenBoundaryTraits_2</code> has been introduced.
	A model of this concept supports curves that approach the open
	boundary of an iso-rectangular area called parameter space, which can
	be unbounded or bounded. The general code of the package, however,
	supports only the unbounded parameter space. We intend to enhance the
	general code to support also bounded parameter spaces in a future
	release.</li>
      <li>The deprecated member function <code>is_at_infinity()</code> of
        <code>Arrangement_2::Vertex</code> has been removed. It has been previously
        replaced new function <code>is_at_open_boundary()</code>.

      <li> The tags in the geometry traits that indicate the type of boundary of
       the embedding surface were replaced by the following new tags:
<pre>
         Left_side_category
         Bottom_side_category
         Top_side_category
         Right_side_category
</pre>
       It is still possible not to indicate the tags at all. Default values are assumed. This however will
       produce warning messages, and should be avoided.</li>
</ul>
</div>


<h2 id="release3.8">Release 3.8 </h2>
<DIV>
<p> Release date: April 2011</p>

<p>
CGAL 3.8 offers the following improvements and new functionality :  </p>

<h3>General</h3>
<ul>
  <li>Boost version 1.39 at least is now required.</li>
  <li>Initial support for the LLVM Clang compiler (prereleases of version 2.9).</li>
  <li>Full support for the options -strict-ansi of the Intel Compiler 11,
  and -ansi of the GNU g++ compiler.</li>
  <li>Adding a concept of ranges. In the following releases, it will be the
      way to provide a set of objects (vs. a couple of iterators).</li>
  <li>Fix a memory leak in CORE polynomials.</li>
  <li>Various fixes in the manual.</li>
</ul>

<h3>3D Mesh Generation (major new feature added)</h3>
<ul>
  <li>Adding the possibility to handle sharp features: the 3D Mesh
 generation package now offers the possibility to get in the final mesh an
 accurate representation of 1-dimensional sharp features present in the
 description of the input domain.
</ul>

<h3>2D Triangulations (major new feature added)</h3>
<ul>
  <li>Add a way to efficiently insert a range of points with information
      into a 2D Delaunay and regular triangulation.
  <li>Add member function mirror_edge taking an edge as parameter.
  <li>Fix an infinite loop in constrained triangulation.
</ul>

<h3>3D Triangulations (major new feature added)</h3>
<ul>
  <li>Add a way to efficiently insert a range of points with information into
      a 3D Delaunay and regular triangulation.
  <li>Add a member function to remove a cluster of points from a Delaunay or
      regular triangulation.
  <li>function vertices_in_conflict is renamed vertices_on_conflict_zone_boundary
      for Delaunay and regular triangulation. Function vertices_inside_conflict_zone
      is added to regular triangulation.
  <li>Structural filtering is now internally used in locate function of Delaunay
      and regular triangulation. It improves average construction time by 20%.
  <li>Added demo.
</ul>

<h3>3D Alpha Shapes (major new feature added)</h3>
<ul>
  <li> The new class Fixed_alpha_shape_3 provides a robust and
       faster way to compute one alpha shape (with a fixed value of alpha).
</ul>


<h3>AABB tree</h3>
<ul>
  <li>Adding the possibility to iteratively add primitives to an existing
      tree and to build it only when no further insertion is needed.
</ul>

<h3>2D and 3D Kernel</h3>
<ul>
  <li>Better handling of 2D points with elevation (3D points projected onto
      trivial planes). More general traits classes (Projection_traits_xy_3,
      Projection_traits_yz_3,Projection_traits_yz_3) are provided to work with
      triangulations, algorithms on polygons, alpha-shapes, convex hull algorithm...
      Usage of former equivalent traits classes in different packages is now deprecated.
  <li>Exact_predicates_exact_constructions_kernel now better use the static filters
      which leads to performance improvements.
  <li>Add an overload for the global function angle, taking three 3D points.
  <li>In the 2D and 3D kernel concept, the constant Boolean Has_filtered_predicates
      is now deprecated. It is now required to use Has_filtered_predicates_tag
      (being either Tag_true or Tag_false).
  <li>Compare_distance_2 and Compare_distance_3 provide additional operators
      for 3 and 4 elements.
  <li>Add intersection test and intersection computation capabilities
      between an object of type Ray_3 and either an object of type Line_3, Segment_3 or Ray_3.
  <li>Improve intersection test performance between an object of type Bbox_3 and an object of type
      Plane_3 or Triangle_3 by avoiding arithmetic filter failures.
</ul>

<h3>2D Envelope</h3>
<ul>
  <li>Env_default_diagram_1 is deprecated, Envelope_diagram_1 should be used instead.
</ul>

<h3>3D Envelope</h3>
<ul>
  <li>A new demo program called <tt>L1_Voronoi_diagram_2</tt> has been
    introduced. It demonstrates how 2D Voronoi diagrams of points under
    the L1 metric are constructed using lower envelopes.
</ul>


<h3>dD Kernel</h3>
<ul>
  <li>Add functor Compute_coordinate_d to Kernel_d concept.
</ul>

<h3>Geometric Object Generators</h3>
<ul>
  <li> CGAL::Random uses boost::rand48 instead of std::rand.
  <li>Adding to CGAL::Random a way to generate random integers.
  <li>Adding generators for dD points.
</ul>

<h3>Algebraic Foundations</h3>
<ul>
  <li>Algebraic_structure_traits now provides an Inverse functor for Fields.
      There is also a new global function inverse.
</ul>

<h3>Bounding Volumes</h3>
<ul>
  <li> dD Min sphere of spheres has a new traits class for the min sphere of points.
</ul>

<h3>Triangulated Surface Mesh Simplification</h3>
<ul>
  <li>The priority queue internally used to prioritize edge simplifications is no longer
      a relaxed heap but a binomial heap. This fix guarantees that all edges satisfying
      a simplification criteria are removed (if possible).
</ul>

<h3>3D Boolean Operations on Nef Polyhedra</h3>
<ul>
  <li>Allow construction of a 3D nef polyhedron from a 3D polyhedron with normals.
</ul>

<h3>2D Arrangements</h3>
<ul>
  <li>Fix a bug in the method insert_at_vertices of the Arrangement_2 class.
  <li>Fix several bugs in the traits class Arr_Bezier_curve_traits_2 for arrangement of Bezier curves.
</ul>

<h3>2D Minkowski Sums</h3>
<ul>
  <li>A bug in the convolution method was fixed.
</ul>
</DIV>

<h2 id="release3.7">Release 3.7 </h2>
<DIV>
<p> Release date: October 2010</p>

<p>
CGAL 3.7 offers the following improvements and new functionality :  </p>


<h3>General</h3>

  <ul>
  <li>The configuration of CGAL libraries now requires CMake>=2.6.

  <li>Changes in the set of supported platforms:
    <ul>
    <li>GNU g++ 4.5 supported (with or without the compilation option
      -std=c++0x).

    <li>Initial support for the option -strict-ansi of the Intel Compiler 11.
      The CGAL libraries compile with that option, and most CGAL headers
      have been fixed. The packages "3D Boolean Operations on Nef
      Polyhedra" (Nef_3), "Convex Decomposition of Polyhedra"
      (Convex_decomposition_3), and "3D Minkowski Sum of Polyhedra"
      (Minkowski_sum_3) are known to still fail to compile with that
      compiler flag.

    <li>The Microsoft Windows Visual C++ compiler 2010 (VC10), that was
      experimentally supported by CGAL-3.6.1, is now fully supported. Note
      that CMake>=2.8.2 is required for that support.

    <li>The Microsoft Windows Visual C++ compiler 2005 (VC8) is no longer
      supported by the CGAL project since CGAL-3.7.

    <li>With Microsoft Windows Visual C++ (VC9 and VC10), the optional
      dependencies Gmp, Mpfr, Blas, Lapack, Taucs no longer use Boost-style
      name mangling. Only one variant is now provided by the CGAL Windows
      installer (release, with dynamic runtime).
    </ul>
  <li>Some demos now require a version of Qt4 >= 4.3.

  <li>CGAL_PDB is no longer provided with CGAL. An alternative solution for
    people interested in reading PDB files is to use ESBTL
    (http://esbtl.sourceforge.net/).

  <li>Fix issues of the CGAL wrappers around the CORE library, on 64 bits
    platforms.
  </ul>


<h3>Arithmetic and Algebra</h3>
<ul>
  <li> New models Algebraic_kernel_d_1 and Algebraic_kernel_d_2 for the
    corresponding concepts. They provide generic support for various
    coefficient types
</ul>

<h3>Arrangements</h3>
<ul>
  <li> A new model Arr_algebraic_segment_traits_2 of ArrangementTraits_2 that
    supports algebraic curves of arbitrary degree in the plane
</ul>


<h3> 2D Triangulations</h3>
<ul>
  <li>The Delaunay and regular 2D triangulations now use a symbolic
    perturbation to choose a particular triangulation in co-circular cases.

  <li>The return type of the template member function
    insert(It beg, It end), taking an iterator range of points,
    has been changed from int to std::ptrdiff_t.

  <li>Classes Triangulation_euclidean_traits_xy_3, Triangulation_euclidean_traits_yz_3
    and Triangulation_euclidean_traits_xz_3 are now model of the concept
    ConstrainedTriangulationTraits_2. They can be used with and without intersection
    of constraints.

  <li>2D Delaunay and basic triangulations now provide vertex relocation by
    the mean of these two new methods: move and move_if_no_collision. The
    methods are also available for the hierarchy
    (Triangulation_hierarchy_2).

</ul>

<h3>3D Triangulations</h3>
   <ul>
  <li>The return type of the template member function
    insert(It beg, It end), taking an iterator range of points,
    has been changed from int to std::ptrdiff_t.
  <li>3D Delaunay triangulations now provide vertex relocation by the mean
    of these two new methods: move and move_if_no_collision. This works in
    both Compact_policy and Fast_policy.
</ul>

<h3>2D and 3D Alpha Shapes</h3>
  <ul>
  <li>The type int in the API has been changed to std::size_t
    so that CGAL can deal with large data sets (64 bit addresses).
  </ul>


<h3>2D Mesh Generation</h3>
  <ul>
  <li>The execution of the 2D mesh generator is now deterministic (same at
    each run).
  </ul>

<h3>3D Mesh Generation</h3>
  <ul>
  <li>The efficiency of the 3D mesh generator has been improved (the number
    of calls to the oracle per inserted vertex has globally decrease).
    This is achieved through a slight change of the mesh generator strategy
    which implies that a surface component that is not detected at the
    surface mesher level will never be discovered by chance, owing to the
    refinement of some tetrahedra, as it could happen before.
    Please note that defining the macro
    CGAL_MESH_3_USE_OLD_SURFACE_RESTRICTED_DELAUNAY_UPDATE switches back to
    the old behavior.

  <li>A demo program is now available.
  </ul>

<h3>Surface Reconstruction from Point Sets</h3>
  <ul>
  <li>Improved performance and minor bug fix.
  </ul>


<h3>2D Range and Neighbor Search</h3>
  <ul>
  <li>The type int in the API has been changed to std::size_t
    so that CGAL can deal with large data sets (64 bit addresses).
</ul>

</DIV>



<h2 id="release3.6.1">Release 3.6.1</h2>

<DIV>
<p>Release date: June 2010</p>

<p>
This is a bug fix release. The following has been changed
since CGAL-3.6:</p>

<h3>General</h3>

  <ul>
  <li> Fix compilation errors with recent Boost versions (since 1.40).

  <li> Initial support for the Microsoft Visual C++ compiler 10.0 (MSVC
    2010). For that support, CMake>=2.8.2 is required.
    Note also that the compiler option "/bigobj" is necessary to compile
    some CGAL programs with MSVC 2010.
</ul>


<h3>Polynomial</h3>
<ul>
  <li>Fix compilation errors with the Microsoft Visual C++ compiler and the
    Intel C++ compiler.
</ul>

<h3> Polyhedron</h3>
<ul>
  <li> Fix a compilation errors in demo/Polyhedron/:
     <li> issue with the location of qglobal.h of Qt4 on MacOS X,
     <li> missing texture.cpp, if TAUCS is used,
  <li> Fix the location of built plugins of demo/Polyhedron/, when CGAL is
    configured with WITH_demos=ON
</ul>

<h3> 3D Periodic Triangulations</h3>
<ul>
  <li> Fixed bug in the triangulation hierarchy for periodic triangulations.
</ul>

<h3> 2D Mesh Generation</h3>
<ul>
   <li> Fix a bug that lead to precondition violation.
  <li> Improve the user manual about the member function is_in_domain() of the
    Face type.
  <li> The 2D meshing process is now deterministic (sorting of bad faces no
    longer relies on pointers comparisons).
</ul>

<h3> 3D Mesh Generation</h3>
<ul>
  <li>Fix a linking errors (duplicate symbols) when <code>&lt;CGAL/refine_mesh_3.h&gt;</code> is
    included in different compilation units.
</ul>

<h3> Spatial Searching</h3>
<ul>
  <li> Fix a bug in <code>&lt;CGAL/Orthogonal_k_neighbor_search.h&gt;</code> when several
    nearest neighbors are at the same distance from the query point.
</ul>

<h3> IO Streams</h3>
<ul>
  <li>Fix a bug in <code>&lt;CGAL/IO/VRML_2_ostream.h&gt;</code> that generated VRML 2 files with
    an invalid syntax for IndexedFaceSet nodes.
</ul>

<h3> Triangulation_2</h3>
<ul>
  <li> Add missing Compare_distance_2 functor in trait classes Triangulation_euclidean_traits_xy_3
    Triangulation_euclidean_traits_yz_3 and Triangulation_euclidean_traits_xz_3.
    This was preventing calling member function nearest_vertex of Delaunay_triangulation_2
    instantiated with one of these traits.
    </ul>
</DIV>

<h2 id="release3.6">Release 3.6</h2>

<DIV>
<p>Release date: March 2010</p>

<p>
CGAL 3.6 offers the following improvements and new functionality : </p>

<h3>General</h3>

  <ul><li> Boost version 1.34.1 at least is now required.</ul>


<h3>Arithmetic and Algebra</h3>

<h4>Algebraic Kernel (new package)</h4>

  <ul>
    <li> This new package is targeted to provide black-box implementations of
    state-of-the-art algorithms to determine, compare and approximate real
    roots of univariate polynomials and bivariate polynomial systems. It
    includes models of the univariate algebraic kernel concept, based on
    the library RS.
  </ul>

<h4>Number Types</h4>

  <ul>
    <li>Two new arbitrary fixed-precision floating-point number types have been
    added: the scalar type Gmpfr and the interval type Gmpfi, based on the
    MPFR and MPFI libraries respectively.
  </ul>


<h3>Geometry Kernels</h3>

<h4>2D and 3D Geometry Kernel</h4>
<ul>
<li> Add new do_intersect() and intersection() overloads:
  <ul>
    <li> do_intersect(Bbox_3, Bbox_3/Line_3/Ray_3/Segment_3)
    <li> intersection(Triangle_3, Line_3/Ray_3/Segment_3)
  </ul>
</ul>

<h3>Polygons</h3>

<h4>2D Regularized Boolean Set-Operations</h4>
<ul>
<li> Fixed General_polygon_set_2::arrangement() to return the proper type
    of object.
</ul>


<h3>Arrangement</h3>

<h4>2D Arrangements</h4>

<ul><li> Fixed passing a (const) traits object to the constructor of Arrangement_2.

<li> Introduced Arrangement_2::fictitious_face(), which returns the fictitious
    face in case of an unbounded arrangement.

<li> Fixed a bug in Bezier-curve handling.

<li> Added (back) iterator, number_of_holes(), holes_begin(), and holes_end()
    to the default DCEL for backward compatibility.

<li> Added (simple) versions of the free overlay() function. It employs the
    default overlay-traits, which practically does nothing.
</ul>

<h3> Polyhedron</h3>
<ul>
  <li> Fix a compilation errors in demo/Polyhedron/:
   <ul>
     <li> issue with the location of qglobal.h of Qt4 on MacOS X,
     <li> missing texture.cpp, if TAUCS is used,
   </ul>
  <li> Fix the location of built plugins of demo/Polyhedron/, when CGAL is
    configured with WITH_demos=ON
  <li> Fix a bug in test_facet function of the incremental builder:
    the function did not test if while a new facet makes a vertex manifold,
    no other facet incident to that vertex breaks the manifold property.
</ul>

<h3>Triangulations and Delaunay Triangulations</h3>

<h4>2D/3D Regular Triangulations</h4>

<ul><li> Weighted_point now has a constructor from Cartesian coordinates.
</ul>

<h4>3D Triangulations</h4>

<ul><li> Regular_triangulation_3 : semi-static floating-point filters are now used
    in its predicates, which can speed up its construction by a factor of about 3
    when Exact_predicates_inexact_constructions_kernel is used.

<li> The class Regular_triangulation_filtered_traits_3 is deprecated, the class
    Regular_triangulation_euclidean_traits_3 must be used instead. The
    predicates of that traits will be filtered if the kernel given as template
    parameter of that traits is itself a filtered kernel.

<li> Triangulation_hierarchy_3 is now deprecated, and replaced by a simpler
    CGAL::Fast_location policy template parameter of Delaunay_triangulation_3.

<li> The old version of remove() (enabled with CGAL_DELAUNAY_3_OLD_REMOVE)
    has been deleted.
</ul>

<h4>3D Periodic Triangulations</h4>

<ul><li> New demo: 3D periodic Lloyd algorithm.

<li> New functionality for Voronoi diagrams: dual of an edge and of a vertex,
    volume and centroid of the dual of a vertex.

<li> The package can now be used with the 3D Alpha Shapes package to compute
    periodic alpha shapes.
</ul>

<h4>3D Alpha shapes</h4>

<ul><li> The class Weighted_alpha_shape_euclidean_traits_3 is deprecated, the class
    Regular_triangulation_euclidean_traits_3 must be used instead.

<li> The package can now be used together with the 3D Periodic Triangulation
    package to compute periodic alpha shapes.
</ul>

<h4>2D/3D Triangulations, 2D Segment Delaunay Graph, 2D Apollonius Graph,
  and 3D Periodic Triangulations</h4>

<ul><li>The constructor and insert function taking ranges now produce
    structures whose iterator orders is now deterministic (same at each
    run).
</ul>


<h3>Mesh Generation</h3>

<h4>2D Mesh Generation</h4>

<ul><li> The 2D mesh generator can now be used with a constrained Delaunay
    triangulation with constraints hierarchy
    (Constrained_triangulation_plus_2).
    <li> In some cases (refinement of a constrained edge that is on the
    convex hull), the 2D mesh generator from CGAL-3.4 and CGAL-3.5
    could create invalid triangulations. This bug is now fixed.
</ul>

<h4>3D Mesh Generation</h4>

<ul><li> The mesh generator has been enriched with an optimization phase to
    provide 3D meshes with well shaped tetrahedra (and in particular no
    slivers).  The optimization phase involves four different optimization
    processes: two global optimization processes (ODT and Lloyd), a
    perturber and an exuder. Each of these processes can be activated or
    not, and tuned to the users needs and to available computer resources.
</ul>

<h3>Support library</h3>

<h4>CGAL ipelets</h4>

<ul><li> Add support for version 7 of Ipe.
</ul>

</DIV>


<h2 id="release3.5.1">Release 3.5.1</h2>
<DIV>
<p>Release date: December 2009</p>
<p>
This is a bug fix release.</p>

<h3>Documentation</h3>
<ul>
  <li>Fixes in the documentation (the online documentation of CGAL-3.5 is now
    based on CGAL-3.5.1).
  <li>Fixes to the bibliographic references.
</ul>

<h3>Windows installer</h3>
<ul>
  <li>The Windows installer of CGAL-3.5.1 fixes an issue with downloading of
    precompiled binaries of the external library TAUCS.
</ul>

<h3>Bug fixes in the following CGAL packages</h3>
  <h4>AABB tree</h4>
  <ul>
    <li>Fix a linker issue in do_intersect(Bbox_3,Bbox_3).
    <li>Fix compilation issue in do_intersect(Bbox_3,Ray_3) when using the
      parameters in this order.
  </ul>
  <h4>3D Mesh Generation</h4>
  <ul>
    <li>Fix a bug in initial points construction of a polyhedral surface.
  </ul>
</DIV>



<h2  id="release3.5">Release 3.5</h2>
<DIV>
<p>Release date: October 2009</p>
<p>
  CGAL releases will now be published about every six months. As a transition
  release, CGAL-3.5 has been developed during 9 months from the release
  CGAL-3.4.</p>

<p>Version 3.5 differs from version 3.4 in the platforms that are supported and
  in functionality.  There have also been a number of bug fixes for this release.</p>

<h3>General</h3>
<ul>
  <li>Additional supported platforms:
    <ul>
      <li>GNU g++ 4.4 supported.
      <li>Intel Compiler 11 supported on Linux
    </ul>
  <li>Fixed ABI incompatibilities when mixing CGAL and Boost Program Options
    on Windows/Visual C++ (the compilation flag -D_SECURE_SCL=0 is not
    longer use in Debug mode).
</ul>

<h3>Geometry Kernels</h3>

<h4>3D Spherical Geometry Kernel</h4>
<ul>
  <li>
    Add functionalities to manipulate circles, circular arcs and points
    that belong to the same sphere.

</ul>
<h3>Polygons</h3>

<h4>2D Regularized Boolean Set-Operations</h4>
<ul>
  <li>The polygon validation operations were enhanced and their interface was
    improved. They are now offered as free functions and applied properly.

</ul>
<h4>2D Straight Skeleton and Polygon Offsetting </h4>
<ul>
  <li>Updated the manual to document the new partial skeletons feature
    (already in the code since 3.4)

</ul>

<h3>Arrangements</h3>

<h4>2D Arrangements</h4>
<ul>
  <li>The member function is_at_infinity() of Arrangement_2::Vertex was
    replaced by the new function is_at_open_boundary(). The former is
    deprecated. While still supported in version 3.5, It will not be
    supported in future releases. The member functions boundary_type_in_x()
    and boundary_type_in_y() were permanently replaced by the functions
    parameter_space_in_x() and parameter_space_in_y(), respectively. The 2
    new functions return an enumeration of a new type, namely
    Arr_parameter_space.

  <li> The tags in the geometry traits that indicate the type of boundary of
    the embedding surface were replaced by the following new tags:
    Arr_left_side_tag
    Arr_bottom_side_tag
    Arr_top_side_tag
    Arr_right_side_tag
    In addition, the code was change, and now it is possible not to
    indicate the tags at all. Default values are assumed. This however will
    produce warning messages, and should be avoided.

  <li> All operations of the geometry traits-class were made 'const'. This
    change was reflected in the code of this package and all other packages
    that are based on it. Traits classes that maintain state, should
    declare the data members that store the state as mutable.

</ul>
<h4>Envelopes of Surfaces in 3D</h4>
<ul>
  <li> A few bugs in the code that computes envelopes were fixed, in
    particular in the code that computes the envelopes of planes.

</ul>

<h3>Triangulations and Delaunay Triangulations</h3>

<h4>3D Periodic Triangulations (new package)</h4>

<ul>
  <li> This package allows to build and handle triangulations of point sets in
    the three dimensional flat torus. Triangulations are built
    incrementally and can be modified by insertion or removal of
    vertices. They offer point location facilities.

</ul>

<h3>Mesh Generation</h3>

<h4>Surface Reconstruction from Point Sets (new package)</h4>
<ul>
  <li> This CGAL package implements an implicit surface reconstruction method:
    Poisson Surface Reconstruction. The input is an unorganized point set
    with oriented normals.

</ul>
<h4>3D Mesh Generation (new package)</h4>
<ul>
  <li> This package generates 3 dimensional meshes.  It computes isotropic
    simplicial meshes for domains or multidomains provided that a domain
    descriptor, able to answer queries from a few different types on the
    domain, is given.  In the current version, Mesh_3 generate meshes for
    domain described through implicit functional, 3D images or polyhedral
    boundaries.  The output is a 3D mesh of the domain volume and conformal
    surface meshes for all the boundary and subdividing surfaces.

</ul>
<h3>Geometry Processing</h3>

<h4>Triangulated Surface Mesh Simplification</h4>

<ul>
  <li>  BREAKING API change in the passing of the visitor object.

  <li>  Fixed a bug in the link_condition test

  <li>  Added a geometric test to avoid folding of facets

  <li>  Fixed a bug in the handling of overflow in the LindstromTurk
    computations

  <li>  Updated the manual to account for the new visitor interface

</ul>
<h4>Point Set Processing (new package)</h4>

<ul>
  <li>  This packages implements a set of algorithms for analysis, processing,
    and normal estimation and orientation of point sets.

</ul>

<h3>Spatial Searching and Sorting</h3>

<h4>AABB tree (new package)</h4>

<ul>
  <li>This package implements a hierarchy of axis-aligned bounding boxes (a
    AABB tree) for efficient intersection and distance computations between
    3D queries and sets of input 3D geometric objects.

</ul>
<h3>Support Library</h3>

<h4>CGAL_ipelets (new package):</h4>
<ul>
  <li> Object that eases the writing of Ipe's plugins that use CGAL.
    Plugins for CGAL main 2D algorithm are provided as demo.


</ul>
</DIV>


<h2 id="release3.4">Release 3.4</h2>
<DIV>
<p>Release date: January 2009</p>

<p>Version 3.4 differs from version 3.3.1 in the platforms that are supported and
in functionality.  There have also been a number of bug fixes for this release.
</p>

<h3>General</h3>
<ul>
<li> GNU g++ 4.3 supported.  Support for g++ 3.3 is dropped.
<li> Visual 9 supported. Support for Visual 7 is dropped.

<li> Boost version 1.33 at least is now required.
<li> CGAL now depends on Boost.Threads, which implies to link against
    a compiled part of Boost.

<li> The new macro CGAL_NO_DEPRECATED_CODE can be defined to disable deprecated code,
    helping users discover if they rely on code that may be removed in
    subsequent releases.

<li> Assertion behaviour:
    It is not possible anymore to set the CONTINUE mode for assertion failures.
    Functions that allow to change the assertion behaviour are now declared in <code>&lt;CGAL/assertions_behaviour.h&gt;</code>.

<li>Qt3 based demos are still there but the documentation has been removed as the CGAL::Qt_Widget will be deprecated.

<li>Qt4 based demos use the Qt GraphicsView framework and the libQGLViewer.
</ul>

<h3> Installation</h3>

<ul>
<li> install_cgal has been replaced by CMake.
</ul>


<h3> Polynomial  (new package)</h3>
<ul>
<li> This package introduces a concept Polynomial_d, a concept for multivariate polynomials in d variables.
</ul>


<h3>Modular Arithmetic (new package)</h3>
<ul>
<li>  This package provides arithmetic over finite fields.
</ul>


<h3>Number Types</h3>
<ul>
<li> the counter Interval_nt::number_of_failures() has been removed, replaced by
    a profiling counter enabled with CGAL_PROFILE.


<li> Fix of a bug in CORE/Expr.h; as a consequence, the arrangement demo works properly when handling
     arrangements of conics, for example, when defining an arc with 5 points.

</ul>



<h3>3D Spherical Geometry Kernel  (new package)</h3>
<ul>
<li> This package is an extension of the linear CGAL Kernel. It offers functionalities on spheres,
    circles, circular arcs and line segments in the 3D space.
</ul>

<h3> Linear Kernel</h3>
<ul>
<li> We recommend that you use the object_cast() function instead of assign()
    to extract an object from a CGAL::Object, for efficiency reasons.
<li> The Kernel archetypes provided by the 2D/3D linear kernel have been removed.
<li> The deprecated linear kernel functors Construct_supporting_line_2 and
    Construct_supporting_line_3 have been removed.
<li> Ambiant_dimension and Feature_dimenison have been added to retrieve the
    potentially compile-time dimension of a space or of an object.
<li> barycenter() functions have been added.

<li> The geometric object Circle_3 as well as predicates and constructions have been added to the kernel

<li>The missing intersection/do_intersect between Line_3 and Line_3 has been added as well.
</ul>


<h3>3D Triangulations</h3>
<ul>
<li> Removed the deprecated functions Cell:mirror_index() and Cell::mirror_vertex().
<li> Derecursification of two functions that in some cases lead to stack overflows
</ul>


<h3>3D Nef Polyhedron</h3>
<ul>
<li> n-ary union/intersection
<li> intersection with halfspace under standard kernel
<li> constructor for polylines
</ul>


<h3>CGAL and the Qt4 GraphicsView (new package)</h3>
<ul>
<li> 2D CGAL Kernel objects and many data structures have can be rendered in a QGraphicsView
</ul>

<h3>STL Extensions:</h3>
<ul>
<li> The functor adaptors for argument binding and composition
    (bind_*, compose, compose_shared, swap_*, negate, along with the helper
    functions set_arity_* and Arity class and Arity_tag typedefs) which were provided
    by <code>&lt;CGAL/functional.h&gt;</code> have been removed.  Please use the better boost::bind
    mecanism instead.  The concept AdaptableFunctor has been changed accordingly
    such that only a nested result_type is required.
<li> The accessory classes Twotuple, Threetuple, Fourtuple and Sixtuple are also
    deprecated (use CGAL::array instead).
<li> CGAL::Triple and CGAL::Quadruple are in the process of being replaced by
    boost::tuple.  As a first step, we strongly recommend that you replace
    the direct access to the data members (.first, .second, .third, .fourth),
    by the get&lt;i&gt;() member function; and replace the make_triple and make_quadruple
    maker functions by make_tuple.<br>
    This way, in a further release, we will be able to switch to boost::tuple more easily.
<li> The class CGAL::Uncertain&lt;&gt; has been documented.  It is typically used to report
    uncertain results for predicates using interval arithmetic, and other filtering
    techniques.
</ul>


<h3>2D Arrangements</h3>
<ul>
  <li> Changed the name of the arrangement package from Arrangement_2 to Arrangement_on_surface_2
    to reflect the potential capabilities of the package to construct and maintain arrangements
    induced by curves embedded on two dimensional surfaces in three space. Most of these capabilities
    will become available only in future releases though.
  <li> Enhanced the geometry traits concept to handle arrangements embedded on surfaces. Each geometry-traits
    class must now define the 'Boundary_category' tag.
  <li> Fixed a bug in Arr_polyline_traits_2.h, where the operator that compares two curves failed to evaluate
    the correct result (true) when the curves are different, but their graphs are identical.
  <li> Permanently removed IO/Arr_postscript_file_stream.h and IO/Polyline_2_postscript_file_stream.h,
    as they depend on obsolete features and LEDA.
  <li> Fixed several bugs in the arrangement demo and enhanced it. e.g., fixed background color change,
    allowed vertex coloring , enabled "smart" color selection, etc.
  <li> Enhanced the arrangement demo with new features, such as allowing the abortion of the merge function
    (de-select), updated the how-to description, etc.
  <li> Replace the functions CGAL::insert_curve(), CGAL::insert_curves(), CGAL::insert_x_monotone_curve(),
    and CGAL::insert_x_monotone_curves() with a single overloaded function CGAL::insert(). The former
    4 functions are now deprecated, and may no longer be supported in future releases.
</ul>

<h3>Envelopes of Surfaces in 3D</h3>

<ul>
<li> Fixed a bug in the computation of the envelope of unbounded planes caused by multiple removals
    of vertices at infinity.
</ul>

<h3>2D Regularized Boolean Set-Operations</h3>
<ul>
  <li> Fixed a bug in connect_holes() that caused failures when connecting holes touching the outer boundary.
  <li> Fixed the concept GeneralPolygonSetTraits_2. Introduced two new concepts GpsTraitsGeneralPolygon_2
    and GpsTraitsGeneralPolygonWithHoles_2. Fixed the definition of the two nested required types Polygon_2
    and Polygon_with_holes_2 of the GeneralPolygonSetTraits_2 concept. They must model now the two new
    concepts above.
  <li> Added a default template parameter to 'General_polygon_set_2' to allow users to pass their specialized
    DCEL used to instantiate the underlying arrangement.
  <li> Enhanced the BOP demo to use multiple windows.
</ul>

<h3>2D Minkowski Sums</h3>
<ul>
 <li> Fixed a few bugs in the approximate offset function, making it robust to highly degenerate inputs.
  <li> Fixed a bug in the exact Minkowski sum computation when processing degenerate inputs that induce overlapping
    of contiguous segments in the convolution cycles.
  <li> Optimized the approximate offset function (reduced time consumption up to a factor of 2 in some cases).
  <li> Added functionality to compute the offset (or to approximate the offset) of a Polygon_with_holes_2
    (and not just of a Polygon_2).
  <li> Added the functionality to compute (or to approximate) the inner offset of a polygon.
</ul>

</DIV>


<h2 id="release3.3.1">Release 3.3.1</h2>
<DIV>
<p>Release date: August 2007</p>

<p>This is a bug fix release.
</p>

<h3>General</h3>
<ul>
<li> Intel C++ 9 was wrongly recognized as unsupported by install_cgal.
<li> Added autolink (for Visual C++) for the CGALImageIO and CGALPDB libraries.
<li> Fixed bug in Memory_sizer when using more than 4GB of memory (64bit).
</ul>

<h3>Number Types</h3>
<ul>
<li> Fixed bug in FPU rounding mode macros (affected only the alpha architecture).
<li> Fixed bug in MP_Float constructor from double for some particular values.
<li> Fixed bug in to_double(Lazy_exact_nt) sometimes returning NaN.
</ul>

<h3>Kernel</h3>
<ul>
<li> Fixed forgotten derivation in Circular_kernel_2::Has_on_2
<li> Added some missing functions in Bbox_3 compared to Bbox_2.
</ul>

<h3>Skin Surface Meshing</h3>
<ul>
<li> The new Skin Surface Meshing package had been forgotten in the list of
  changes and the release announcement of CGAL 3.3:
    This package allows to build a triangular mesh of a skin surface.
    Skin surfaces are used for modeling large molecules in biological computing.
</ul>

<h3>Arrangements</h3>
<ul>
<li> Fixed a bug in the Arrangement_2 package in dual arrangement representation
  for Boost graphs when reporting all halfedges of a face.
<li> Fixed a bug in the Arrangement sweep-line when using a specific polyline
  configuration.
<li> Fixed bug in Arrangement_2 in walk along a line point location for unbounded curves.
<li> Fixed bug in aggregated insertion to Arrangement_2.
<li> Fixed bug in Arrangment_2 class when inserting an unbounded curve from an existing vertex.
<li> Fixed bug when dealing with a degenerate conic arc in Arr_conic_traits_2 of
  the Arrangment package, meaning a line segment which is part of a degenerate
  parabola/hyperbola.
<li> Fixed bug in the Bezier traits-class:
    properly handle line segments.
    properly handle comparison near a vertical tangency.
</ul>

<h3>2D Polygon </h3>
<ul>
<li> Fixed bug in degenerate case of Polygon_2::is_convex() for equal points.
</ul>

<h3>2D Triangulations</h3>
<ul>
<li> Fixed bug in Regular_triangulation_2.
</ul>

<h3>3D Triangulations</h3>
<ul>
<li> Added a circumcenter() function in the default Cell type parameter
     Triangulation_ds_cell_base_3, so that the .dual() member function of
     Delaunay still work as before, without requiring the explicit use of
     Triangulation_cell_base.
<li> Added missing operator-&gt;() to Facet_circulator.
</ul>

<h3>Interpolation</h3>
<ul>
<li> Fixed bug in Interpolation 3D about the normalization coefficient initialization.
</ul>

<h3>3D Boolean Operations on Nef Polyhedra</h3>
<ul>
<li> Fixed bug in construction of Nef_polyhedron_3 from off-file. Now, always the
  inner volume is selected.
<li> Fixed bug in conversion from Nef_polyhedron_3 to Polyhedron_3. Polyhedron_3 was not cleared
  at the beginning.
<li> Fixed bug in Nef_polyhedron_3 in update of indexes for construction of external structure.
</ul>

<h3>Third Party Libraries Shipped with CGAL</h3>
<ul>
<li> TAUCS supports now 64 bits platforms.
<li> CAUTION: Since version 3.3.1, CGAL is no longer compatible with the official
           release of TAUCS (currently 2.2). Make sure to use the version
           modified by the CGAL project and available from the download section
           of http://www.cgal.org.
</ul>

</DIV>



<h2 id="release3.3">Release 3.3</h2>
<DIV>
<p>Release date: May 2007</p>

<p>
Version 3.3 differs from version 3.2.1 in the platforms that are supported and
in functionality.  There have also been a number of bug fixes for this release.
</p>

<p>Additional supported platforms
<ul>
<li> GNU g++ 4.1 and 4.2
<li> Intel C++ compiler 9
<li> Microsoft Visual C++ compiler 8.0
</ul>

<p>The following platforms are no longer supported:

<UL>
   <LI>Intel 8
</UL>

<p>CGAL now supports Visual C++ "Checked iterators" as well as the debug mode
of GNU g++'s STL (-D_GLIBCXX_DEBUG).</p>

<p>CGAL now works around the preprocessor macros 'min' and 'max' defined
in <code>&lt;windows.h&gt;</code> which were clashing with min/max functions.
</p>


<H3>Installation</H3>

<ul>
<li>On Windows the libraries built in Developer Studio now have names
  which encode the compiler version, the runtime and whether it was
  built in release or debug mode. The libraries to link against are
  chosen with linker pragmas in header files.
<li>On all platforms but Windows shared and static versions of the libraries are generated
</ul>

<h3>Manuals</h3>
<ul>
<li> The Package Overview page now also hosts the precompiled demos.
</ul>

<h3>Algebraic Foundations</h3>


<p>
<ul>
  <li>Algebraic Foundations (new package)<br>

This package defines what algebra means for CGAL, in terms of concepts, classes and functions. The main features are: (i) explicit concepts for interoperability of types (ii) separation between algebraic types (not necessarily embeddable into the reals), and number types (embeddable into the reals).

<p>
 <li>Number Types<br>
  Fixed_precision_nt and Filtered_exact number types have been removed.
</ul>

<h3>Kernels</h3>

<p>
<ul>
  <li> 2D Circular Kernel<br>
Efficiency improved through geometric filtering of predicates, introduced with
  the filtered kernel Filtered_bbox_circular_kernel_2<.>, and also chosen for the
  predefined kernel Exact_circular_kernel_2.

  <li> Linear Kernel<br>
 Exact_predicates_exact_constructions_kernel memory and run-time improvements
  through usage of lazy geometric constructions instead of lazy arithmetic.
</ul>

<h3> Data Structures and Algorithms</h3>

<p>
<ul>
<li> Surface Mesh Simplification  (new package)<br>

  This package provides a mesh simplification framework using edge collapse
  operations, and provides the Turk/Lindstrom simplification algorithm.

<p>
<li> Skin Surface Meshing  (new package)<br>

  This package allows to build a triangular mesh of a skin surface.
    Skin surfaces are used for modeling large molecules in biological
    computing. The surface is defined by a set of balls, representing
    the atoms of the molecule, and a shrink factor that determines the
    size of the smooth patches gluing the balls together.

<p>
<li>Estimation of Local Differential Properties  (new package)<br>

  This package allows to compute local differential quantities of a surface from a point sample

<p>
<li>Approximation of Ridges and Umbilics on Triangulated Surface Meshes   (new package)<br>

  This package enables the approximation of differential features on
  triangulated surface meshes. Such curvature related features are
  lines: ridges or crests, and points: umbilics.

<p>
<li>Envelopes of Curves in 2D  (new package)<br>

  This package contains two sets of functions that construct the lower and upper envelope diagram
  for a given range of bounded or unbounded curves.

<p>
<li>Envelopes of Surfaces in 3D  (new package)<br>

  This package contains two sets of functions that construct the lower and upper envelope diagram
  for a given range of bounded or unbounded surfaces. The envelope diagram is realized as a
  2D arrangement.

<p>
<li>Minkowski Sums in 2D  (new package)<br>

  This package contains functions for computing planar Minkowski sums of two closed polygons,
  and for a polygon and a disc (an operation also known as offsetting or dilating a polygon).
  The package also contains an efficient approximation algorithm for the offset computation,
  which provides a guaranteed approximation bound while significantly expediting the running
  times w.r.t. the exact computation procedure.

<p>
<li>Surface Mesh Parametrization<br>

  Added Jacobi and SSOR preconditioners to OpenNL solver, which makes it
  much faster and more stable.

<p>
<li>2D Arrangements<br>

<ul>
<li> Added support for unbounded curves.
<li> Added a traits class that supports bounded and unbounded linear objects,
  namely lines, rays and line segments.
<li> Added traits classes that handle circular arcs based on the circular kernel.
<li> Added a traits class that supports Bezier curves.
<li> Enhanced the traits class that supports rational functions to
  handle unbounded (as well as bounded) arcs
<li> Added a free function called decompose() that produces the symbolic vertical decomposition of a
  given arrangement, performing a batched vertical ray-shooting query from all arrangement vertices.
<li> Fixed a memory leak in the sweep-line code.
<li> Fixed a bug in computing the minor axis of non-degenerate hyperbolas.
</ul>

<li>Boolean Set Operations<br>
<ul>
<li> Added the DCEL as a default template parameter to the General_polygon_set_2 and Polygon_set_2 classes.
  This allows users to extend the DCEL of the underlying arrangement.
<li> Added a function template called connect_holes() that connects the holes in a given polygon with holes,
  turning it into a sequence of points, where the holes are connceted to the outer boundary using
  zero-width passages.
<li> Added a non-const function member to General_polygon_set_2 that obtains the underlying arrangement.
</ul>

<p>
<li>2D and 3D Triangulations<br>
<ul>
<li> The constructors and insert member functions which take an iterator range perform spatial sorting
  in order to speed up the insertion.
</ul>


<p>
<li>Optimal Distances
<br>
<ul>
<li>Polytope_distance_d:
  has support for homogeneous points; bugfix in fast exact version.
</ul>


<p>
<li>Bounding Volumes
<br>
<ul>
<li>Min_annulus_d has support for homogeneous points; bugfix in fast exact version.
</ul>

</ul>

<h3> Support Library</h3>

<ul>
<li>CGAL and the Boost Graph Library (BGL) (new package)<br>

This package provides the glue layer for several CGAL data structures such that
they become models of the BGL graph concept.

<p>
<li>Spatial Sorting  (new package)<br>

This package allows to sort points and other objects along a Hilbert curve
which can improve the performance of algorithms like triangulations.
It is used by the constructors of the triangulation package which have
an iterator range of points as argument.

<p>
<li>Linear and Quadratic Programming Solver  (new package)<br>
This package contains algorithms for minimizing linear and
convex quadratic functions over polyhedral domains, described by linear
equations and inequalities.
</ul>
</DIV>





<h2 id="release3.2.1">Release 3.2.1</h2>
<DIV>
<p>Release date: July 2006</p>

<p>
This is a bug fix release
</p>

<h3> Number Types</h3>
<ul>
  <li> Fix MP_Float constructor which crashed for some values.
</ul>

<h3> Kernel </H3>
<ul>
  <li> Rename Bool to avoid a clash with a macro in X11 headers.
</ul>
<h3> Arrangement</H3>

<ul>
  <li> Derived the Arr_segment_traits_2 Arrangement_2 traits class from the parameterized Kernel.
    This allows the use of this traits class in an extended range of applications that require
    kernel objects and operations on these objects beyond the ones required by the Arrangement_2
    class itself.
  <li> Fixed a compilation bug in the code that handles overlay of arrangements instantiated with
    different DCEL classes.
  <li> Fixed a couple of bugs in the implementation of the Trapezoidal RIC point-location strategy
</ul>

<h3> Triangulation, Alpha Shapes </H3>
<ul>
  <li> Qualify calls to filter_iterator with "CGAL::" to avoid overload ambiguities with
  Boost's filter_iterator.
</ul>

<h3> Surface Mesher</H3>
<ul>
  <li>  Fixed a bug in iterators of the class template Surface_mesh_complex_2_in_triangulation_3
</ul>

<h3> Surface Mesh Parametrisation </H3>
<ul>
  <li>   Updated the precompiled taucs lib
</ul>
<h3> Kinetic Data Structures</H3>
<ul>
  <li> Fixed problems caused by old versions of gcc being confused by operator! and operator int()
  <li> Added point removal support to the Active_objects_vector
</ul>

</DIV>


<h2 id="release3.2">Release 3.2</h2>
<DIV>
<p>Release date: May 2006</p>

<p>
Version 3.2 differs from version 3.1 in the platforms that are supported and
in functionality.  There have also been a number of bug fixes for this release.
</p>

<p>The following platforms are no longer supported:

<UL>
   <LI>SunPro CC versions 5.4 and 5.5 on Solaris
   <LI>SGI Mips Pro
</UL>

<p>
For Visual C++ the installation scripts choose the multi-threaded dynamically
linked runtime (/MD). Before it was the single-threaded static runtime (/ML).</p>


<H3>Installation</H3>

<ul>
<li>The install tool tries to find third party libraries
   at "standard" locations.
<li> Installers for Apple, Windows, and rpms.
</ul>

<h3>Manuals</h3>
<ul>
<li> User and Reference manual pages of a package are in the same chapter
</ul>


<h3>Kernels</h3>

<p>
<ul>
  <li> 2D Circular Kernel (new package)<br>
This package is an extension of the linear CGAL Kernel. It offers functionalities
on circles, circular arcs and line segments in the plane.
</ul>

<h3> Data Structures and Algorithms</h3>

<p>
<ul>
<li>  2D Regularized Boolean Set-Operations (new package)<br>

This package consists of the implementation of Boolean set-operations
on point sets bounded by weakly x-monotone curves in 2-dimensional
Euclidean space. In particular, it contains the implementation of
regularized Boolean set-operations, intersection predicates, and point
containment predicates.

<p>
<li> 2D Straight Skeleton and Polygon Offsetting  (new package)<br>

This package implements an algorithm to construct a halfedge data
structure representing the straight skeleton in the interior of 2D
polygons with holes and an algorithm to construct inward offset
polygons at any offset distance given a straight skeleton.


<p>
<li> 2D Voronoi Diagram Adaptor  (new package)<br>

This package provides an adaptor that adapts a
2-dimensional triangulated Delaunay graph to the corresponding
Voronoi diagram, represented as a doubly connected edge list (DCEL)
data structure. The adaptor has the ability to automatically
eliminate, in a consistent manner, degenerate features of the Voronoi
diagram, that are artifacts of the requirement that Delaunay graphs
should be triangulated even in degenerate configurations. Depending on
the type of operations that the underlying Delaunay graph supports,
the adaptor allows for the incremental or dynamic construction of
Voronoi diagrams and can support point location queries.


<p>
<li>3D Surface Mesher  (new package)<br>

This package provides functions to generate surface meshes that
interpolate smooth surfaces. The meshing algorithm is based on
Delaunay refinement and provides some guarantees on the resulting
mesh: the user is able to control the size and shape of the mesh
elements and the accuracy of the surface approximation. There is no
restriction on the topology and number of components of input
surfaces. The surface mesher may also be used for non smooth surfaces
but without guarantee.

<p>
Currently, implementations are provided for implicit surfaces
described as the zero level set of some function and surfaces
described as a gray level set in a three-dimensional image.</p>


<p>
<li> 3D Surface Subdivision Methods  (new package)<br>

Subdivision methods recursively refine a control mesh and generate
points approximating the limit surface. This package consists of four
popular subdivision methods and their refinement hosts. Supported
subdivision methods include Catmull-Clark, Loop, Doo-Sabin and sqrt(3)
subdivisions. Their respective refinement hosts are PQQ, PTQ, DQQ and
sqrt(3) refinements. Variations of those methods can be easily
extended by substituting the geometry computation of the refinement
host.


<p>
<li>  Planar Parameterization of Triangulated Surface Meshes  (new package)<br>

Parameterizing a surface amounts to finding a one-to-one mapping from
a suitable domain to the surface. In this package, we focus on
triangulated surfaces that are homeomorphic to a disk and on piecewise
linear mappings into a planar domain. This package implements some of
the state-of-the-art surface mesh parameterization methods, such as
least squares conformal maps, discrete conformal map, discrete
authalic parameterization, Floater mean value coordinates or Tutte
barycentric mapping.


<p>
<li> Principal Component Analysis  (new package)<br>

This package provides functions to compute global informations on the
shape of a set of 2D or 3D objects such as points. It provides the
computation of axis-aligned bounding boxes, centroids of point sets,
barycenters of weighted point sets, as well as linear least squares
fitting for point sets in 2D, and point sets as well as triangle sets
in 3D.


<p>
<li>2D Placement of Streamlines  (new package)<br>

Visualizing vector fields is important for many application domains. A
good way to do it is to generate streamlines that describe the flow
behaviour. This package implements the "Farthest Point Seeding"
algorithm for placing streamlines in 2D vector fields. It generates a
list of streamlines corresponding to an input flow using a specified
separating distance. The algorithm uses a Delaunay triangulation to
model objects and adress different queries, and relies on choosing the
centers of the biggest empty circles to start the integration of the
streamlines.


<p>
<li>  Kinetic Data Structures  (new package)<br>

Kinetic data structures allow combinatorial structures to be
maintained as the primitives move. The package provides
implementations of kinetic data structures for Delaunay triangulations
in two and three dimensions, sorting of points in one dimension and
regular triangulations in three dimensions. The package supports exact
or inexact operations on primitives which move along polynomial
trajectories.


<p>
<li>   Kinetic Framework  (new package)<br>

Kinetic data structures allow combinatorial geometric structures to be
maintained as the primitives move. The package provides a framework to
ease implementing and debugging kinetic data structures. The package
supports exact or inexact operations on primitives which move along
polynomial trajectories.


<p>
<li> Smallest Enclosing Ellipsoid   (new package)<br>

This algorithm is new in the chapter Geometric Optimisation.

<p>
<li>  2D Arrangement (major revision)<br>

This package can be used to construct, maintain, alter, and display
arrangements in the plane. Once an arrangement is constructed, the
package can be used to obtain results of various queries on the
arrangement, such as point location. The package also includes generic
implementations of two algorithmic frameworks, that are, computing the
zone of an arrangement, and line-sweeping the plane, the arrangements
is embedded on.

<p>
Arrangements and arrangement components can also be extended to store
additional data. An important extension stores the construction
history of the arrangement, such that it is possible to obtain the
originating curve of an arrangement subcurve.</p>


<p>
<li>   Geometric Optimisation (major revision)<br>

The underlying QP solver which is the foundation for several algorithms
in the Geometric Optimisation chapter has been completely rewritten.

<p>
<li>3D Triangulation (new functionality)<br>

Regular_triangulation_3 now offers vertex removal.

</ul>


</DIV>

<h2 id="release3.1">Release 3.1</h2>
<DIV>
<p>Release date: December 2004</p>
<p>Version 3.1 differs from version 3.0 in the platforms that are supported and
in functionality.  There have also been a number of bug fixes for this release.</p>


<p>
Additional supported platforms:
<UL>
   <LI> MS Visual C++, version 7.3. and 8.0
   <LI> Intel 8.0
   <LI> SunPro CC versions 5.4 and 5.5 on Solaris
   <LI> GNU g++ versions 3.4 on Linux, Solaris, Irix, cygwin, FreeBSD, and MacOS X
  <LI> Darwin (MacOS X) and IA64/Linux support.
</UL>
<p>
The following platforms are no longer supported:
<UL>
   <LI>MS Visual C++, version 7.0
</UL>

<p>
The following functionality has been added or changed:<BR><BR>

<H3>All</H3>
<UL>
    <LI> The  CORE 1.7 library for exact
      real arithmetic.
    <LI>Updated  GMP to 4.1.3.
    <LI>Added Mpfr a library for multiple-precision floating-point computations with exact rounding.
    <LI>Added Boost 1.32.0 (only include files).
</UL>

<H3>Installation</H3>
<UL>
   <LI> new option --disable-shared to omit building libCGAL.so.
</UL>


<H3>Manuals</H3>
<UL>
    <LI> Merged all major manuals in one multi-part manual, which provides
      now cross-links between the CGAL Kernel, the CGAL Basic Library,
      and the CGAL Support Library HTML manuals.

    <LI> Improved layout.
</UL>

<H3>Kernels</H3>

<UL>
   <LI> Improved efficiency of filtered kernels.
   <LI>More predicates and constructions.
</UL>


<H3>Basic Library</H3>


<UL>
  <LI> 2D Segment Voronoi Diagram (new package)<BR>

A data structure for Voronoi diagrams of segments in the plane under the Euclidean metric. The Voronoi edges
are arcs of straight lines and parabolas. The algorithm provided in this package is incremental.
</LI>

<LI>  2D Conforming Triangulations and Meshes (new package)<BR>

An implementation of Shewchuk's algorithm  to construct conforming triangulations and 2D meshes.
</LI>



  <LI> 3D Boolean Operations on  Nef Polyhedra (new package)<BR>
A new class (Nef_polyhedron_3) representing 3D Nef polyhedra, a
      boundary representation for cell-complexes bounded by halfspaces
      that supports boolean operations and topological operations in full
      generality including unbounded cells, mixed dimensional cells (e.g.,
      isolated vertices and antennas). Nef polyhedra distinguish between
      open and closed sets and can represent non-manifold geometry.

</LI>

<LI>  2D and Surface Function Interpolation (new package)<BR>

This package implements different methods for scattered data interpolation: Given
measures of a function on a set of discrete data points, the task is
to interpolate this function on an arbitrary query point. The package
further offers functions for natural neighbor interpolation.

</LI>

 <LI> Planar Nef polyhedra embedded on the sphere (new package)<BR>
      A new class (Nef_polyhedron_S2) designed and supported mainly to
      represent sphere neighborhoods around vertices of the three-
      dimensional Nef polyhedra.
</LI>

 <LI> Box_intersection_d (new package)<BR>

      A new efficient algorithm for finding all intersecting pairs for
      large numbers of iso-oriented boxes, i.e., typically these will be
      bounding boxes of more complicated geometries. Useful for (self-)
      intersection tests of surfaces etc.
</LI>


<LI>  2D Snap Rounding (new package)<BR>

Snap Rounding is a well known method for converting
arbitrary-precision arrangements of segments into a fixed-precision
representation. In the study of robust geometric
computing, it can be classified as a finite precision approximation
technique. Iterated Snap Roundingis a modification
of Snap Rounding in which each vertex is at least half-the-width-of-a-pixel away
from any non-incident edge. This package supports both
methods.
</LI>

<LI>3D Triangulations

<UL>
 <LI> Triangulation_3: added operator==(),removed push_back() and copy_triangulation().
<LI> Delaunay_3 : added nearest_vertex(), move_point(), vertices_in_conflict().
<LI> Regular_3 :  added filtered traits class, and nearest_power_vertex().
</UL>


<LI> Planar_map and Arrangement_2

<UL>
<LI> The interface of the two traits functions that compute the intersection of two given curves changed. The functions nearest_intersection_to_right() and nearest_intersection_to_left() return an object of type CGAL::Object that represents either an empty intersection, a point, or an overlapping subcurve.
<LI> Requirements to define two binary tags were added to the traits concept of the Planar_map as follows:
<EM>Has_left_category</EM> - indicates whether the functions curves_compare_y_at_x_left() and nearest_intersection_to_left() are implemented in the traits model.
<EM>Has_reflect_category</EM> - indicates whether the functions point_reflect_in_x_and_y() and curve_reflect_in_x_and_y() are implemented in the traits model. They can be used as an alternative to the two function in the previous item.
<LI> A new constructor of the Segment_cached_2 type that represents a segment in the Arr_segment_cached_traits_2 traits class was introduced. The new constructor accepts the segment endpoints as well as the coefficients of the underlying line.
<LI> A new version of the conic-arc traits, based on CORE version 1.7 was introduced. This new traits class makes use of CORE's rootOf() operator to compute the intersection points in the arrangement, making its code much simpler and more elegant than the previous version. In addition, new constructors for conic arcs are provided. The new traits class usually performs about 30% faster than the version included in CGAL 3.0
<LI> The traits class that handles continuous piecewise linear curves, namely Arr_polyline_traits_2, was rewritten. The new class is parametrized with a traits class that handles segments, say Segment_traits. The polyline curve defined within the Arr_polyline_traits_2 class is implemented as a vector of segments of type Segment_traits::Curve_2.
<LI> A meta traits class, namely Arr_curve_data_traits_2,  that extends the curve type of the planar-map with arbitrary additional data was introduced. It should be instantiated with a regular traits-class and a class that contains all extraneous data associated with a curve.
<LI>  The class that represents the trapezoidal-decomposition point location strategy was renamed to Pm_trapezoid_ric_point_location.
<LI> The Arrangement demo was rewritten. It covers many more features, has a much better graphical user interface, and comes with online documentation.
<LI> Few bugs in the sweep-line module related to overlapping vertical segments were fixed. This module is used by the aggregate insert method that inserts a collection of curves at once.
</UL>


<LI>Triangulation_2

<UL>
<LI> added a filtered trait class in the regular triangulation
<LI> added split and join operations in the triangulation data structure class
</UL>

<LI>Alpha_shapes_3

<UL>
<LI>major changes in the implementation of the class Alpha_shapes_3.
<LI>New implementation results in a true GENERAL mode
    allowing null and negative alpha-values. It also fixed the edges classification bug
    and introduces a classification of vertices.
</UL>

<LI>Min_ellipse_2

<UL>
 <LI> made access to approximate double representation public
 <LI> fixed bugs in conversion to double representation
 <LI> added <TT>is_circle()</TT> method
 <LI> minor performance improvements
</UL>

<LI>Min_sphere_of_spheres_d:

<UL>
<LI> The models

    <TT>Min_sphere_of_spheres_d_traits_2&lt;K,FT,UseSqrt,Algorithm&gt;</TT>,
    <TT>Min_sphere_of_spheres_d_traits_3&lt;K,FT,UseSqrt,Algorithm&gt;</TT>, and
    <TT>Min_sphere_of_spheres_d_traits_d&lt;K,FT,Dim,UseSqrt,Algorithm&gt;</TT>

  of concept <TT>MinSphereOfSpheresTraits</TT> now represent a sphere
  as a <TT>std::pair&lt;Point,Radius&gt;</TT> (and not any more as a
  <TT>CGAL::Weighted_point&lt;Point,Weight&gt;</TT>)
<LI> Internal code cleanup; in particular, implementation details
  don't pollute the namespace CGAL anymore
</UL>


<LI>Polyhedron_3

<UL>
      <LI> New Tutorial on CGAL Polyhedron for Subdivision Algorithms with
        interactive demo viewer in source code available.

      <LI> Added example program for efficient self-intersection test.
      - Added small helper functions, such as vertex_degree, facet_degree,
        edge_flip, and is_closed.
</UL>

<LI> Apollonius Graph (Voronoi of Circles)

 <UL>
       <LI> Reduced memory requirements by approximately a factor of two.
 </UL>

</UL>

</DIV>


<h2 id="release3.0.1">Release 3.0.1</h2>
<DIV>
<p>Release date: February 2004</p>

<p>This is a bug-fix release.
No new features have been added in 3.0.1.  Here is the list of bug-fixes.<p>

<H3> Polyhedral Surface</H3>

<ul>
  <li>Fixed wrong include files for output support. Added example.
</ul>

<H3>Planar_map</H3>

<ul>
  <li>Fixed the so called "Walk-along-a-line" point-location strategy to
      correctly handle a degenerate case.
</ul>

<H3>2D Triangulation</H3>

<ul>
  <li> added missing figure in html doc
  <li> in  Line_face_circulator_2.h:<br>
       Fixed changes made to support handles with a typedef to iterator.
       The fix concerns operator== and !=.
</ul>

<H3>Alpha_shapes_3</H3>

<ul>
  <li>fixed classify member function for edges.
</ul>


<H3>  Number types</H3>

<ul>
  <li>Lazy_exact_nt:
    <ul>
      <li>added the possibility to select the relative precision of
          <tt>to_double()</tt> (by default 1e-5).  This should fix reports
          that some circumcenters computations have poor coordinates,
          e.g. nan).
      <li>when exact computation is triggered, the interval is recomputed,
          this should speed up some kinds of computations.
    </ul>
  <li><tt>to_interval(Quotient&lt;MP_Float&gt;)</tt>: avoid spurious overflows.
</ul>

<H3>Kernel</H3>

<ul>
  <li>
  missing acknowledgment in the manual and minor clarification of

     <tt>intersection()</tt> documentation.
</ul>

</div>

<h2 id="release3.0">Release 3.0</h2>
<DIV>

<p>Release date: October 2003 </p>

<p>Version 3.0 differs from version 2.4 in the platforms that are supported and
in functionality.  There have also been a number of bug fixes for this release.</p>

<p>The license has been changed to either the LGPL (GNU Lesser General Public
License v2.1) or the QPL (Q Public License v1.0) depending on each package.
So CGAL remains free of use for you, if your usage meets the criteria of these
licenses, otherwise, a commercial license has to be purchased from
GeometryFactory.</p>

<p>
Additional supported platforms:
<UL>
   <LI> MS Visual C++, version 7.1.
   <LI> SunPro CC versions 5.4 and 5.5 on Solaris
   <LI> GNU g++ versions 3.2 and 3.3 on Linux, Solaris, Irix, cygwin, and FreeBSD.
   <LI> MipsPRO CC 7.30 and 7.40 with both the n32 and n64 ABIs.
</UL>
<p>
The following platforms are no longer supported:
<UL>
   <LI>MS Visual C++, version 6.
   <LI>  GNU g++ 2.95.2 (2.95.3 is still supported)
   <LI>  Kai C++ and Borland C++, all versions
</UL>

<p>
The following functionality has been added or changed:<BR><BR>

<B>All</B>
<UL>
    <LI> The  CORE library for exact
      computations is now distributed as part of CGAL as well.
</UL>


<H3>Kernels</H3>


<UL>
   <LI>3 typedefs have been added to ease the choice of a robust and fast kernel:
     <UL>
      <LI> Exact_predicates_inexact_constructions_kernel
      <LI> Exact_predicates_exact_constructions_kernel
      <LI> Exact_predicates_exact_constructions_kernel_with_sqrt
     </UL>
    <LI> Progress has been made towards the complete adaptability and
      extensibility of our kernels.
    <LI> New faster Triangle_3 intersection test routines.
		<br><i>(see Erratum)</i>
    <LI> Added a Kernel concept archetype to check that generic algorithms
      don't use more functionality than they should.
    <LI> A few more miscellaneous functions.
</UL>

<H3>Basic Library</H3>

<UL>
  <LI> 2D Apollonius Graph (new package)<BR>
Algorithms for computing the Apollonius
      graph in two dimensions.  The Apollonius graph is the dual of the
      Apollonius diagram, also known as the additively weighted Voronoi
      diagram.  The latter can be thought of as the Voronoi diagram of a set
      of circles under the Euclidean metric, and it is a generalization of the
      standard Voronoi diagram for points.  The algorithms provided are
      dynamic.

  <LI>dD Min Sphere of Spheres (new package)<BR>
      Algorithms to compute the smallest
      enclosing sphere of a given set of spheres in R<sup>d</sup>.
      The package provides
      an algorithm with maximal expected running time
      <i>O(2<sup>O(d)</sup> n)</i> and a
      fast and robust heuristic (for dimension less than 30).

<LI>Spatial Searching (new package)<BR>
Provides exact and approximate distance
      browsing in a set of points in <i>d</i>-dimensional space using
      implementations of algorithms supporting:
      <ul>
        <li> both nearest and furthest neighbor searching
        <li> both exact and approximate searching
        <li> (approximate) range searching
        <li> (approximate) <i>k</i>-nearest and <i>k</i>-furthest neighbor
             searching
        <li> (approximate) incremental nearest and incremental furthest neighbor
          searching
        <li> query items representing points and spatial objects.
      </ul>

 <LI><B>Kd-tree</b><br>
this package is deprecated, its documentation is removed.
      It is replaced by the Spatial Searching package.

  <LI>Largest_empty_rectangle_2<BR>
       Given a set of points P in the plane, the class
       Largest_empty_iso_rectangle_2 is a data structure that
       maintains an iso-rectangle with the largest area among all
       iso-rectangles that are inside a given iso-rectangle bounding box,
       and that do not contain any point of the point set P.

<LI> 2D Triangulation and
     3D Triangulation<BR>
     <UL>
      <LI> The classes Triangulation_data_structure_2 (and 3), which implements
        the data structure for 2D triangulation class, now makes use of
        CGAL::Compact_container (see Support Library section below).
      <LI> The triangulation classes use a Rebind mecanism to provide
        the full flexibility on Vertex and Face base classes.
        This means that it is possible for the user to derive its own Face
        of Vertex base class, adding a functionality that makes use of
        types defined by the triangulation data structure like Face_handle
        or Vertex_handle.
      <LI> New classes Triangulation_vertex_base_with_info_2 (and 3) and
	Triangulation_face_base_with_info_2 (and 3) to make easier the
        customisation of base classes in most cases.
     </UL>

<LI> 2D Triangulation<BR>
     <UL>
      <LI> Regular triangulation provides an easy access to hidden points.
      <LI> The Triangulation_hierarchy_2, which provide an efficient location
	data structure, can now be used with any 2D triangulation class plugged
        in (including Regular triangulations).
      </ul>

<LI> 3D Triangulation<BR>
     <UL>
     <LI> faster vertex removal function in Delaunay_triangulation_3.
      <LI> Delaunay_triangulation_3 is now independent of the order of insertions
        of the points (in case of degenerate cosphericity).
      <LI>Regular_triangulation_3 now hides vertices (and updates itself) when
        inserting a coinciding point with greater weight.  This required a new
        predicate.
      <LI> deprecated functions: copy_triangulation(), push_back(),
        set_number_of_vertices().
      <LI> Triangulation_3 now gives non-const access to the data structure.
     </UL>

<LI> Interval Skip List (new package)<BR>
An interval skip list is a data strucure for finding all intervals
      that contain a point, and for stabbing queries, that is for answering
      the question whether a given point is contained in an interval or not.

<LI>
       Planar Maps and

       Arrangements<BR>

 The changes concern mainly the traits classes.
      <OL>
        <LI> New traits hierarchy and interface:
           The set of requirements was made sound and complete. A couple of
	   requirements were eliminated, few others were redefined, and some
	   were renamed. A hierarchy of three traits classes for the
	   Planar_map_2, Planar_map_with_intersections_2, and Arrangement_2
	   types was established to include only the necessary requirements at
           each level. It was determined that for the aggregate insertion-
	   operation based on a sweep-line algorithm only a subset of the
	   requirements is needed. Preconditions were added where appropriate
	   to tighten the requirements further.

           <p>
           The following functions have been renamed:
           <UL>
           <LI> point_is_same() renamed to point_equal()
           <LI> curve_is_same() renamed to curve_equal()
           <LI> curve_is_in_x_range() renamed to point_in_x_range()
           <LI> curve_compare_at_x() renamed to curves_compare_y_at_x()
             Furthermore, a precondition has been added that the reference
	     point is in the x-range of both curves.
           <LI> curve_compare_at_x_right() renamed to
	     curves_compare_y_at_x_to_right().
             Furthermore, a precondition has been added that both curves are
	     equal at the reference point and defined to its right.
           <LI> curve_compare_at_x_left() renamed to
	     curves_compare_y_at_x_to_left().
             Furthermore, a precondition has been added that both curves are
	     equal at the reference point and defined to its right.
           <LI> curve_get_point_status() renamed to curve_compare_y_at_x().
             Furthermore, a precondition has been added that the point is in
	     the x-range of the curve. Consequently, the function now returns a
	     Comparison_result (instead of a special enum).
           <LI> make_x_monotone() renamed to curve_make_x_monotone()
             See more details below.
           <LI> curve_flip() renamed to curve_opposite()
           </UL>

           The following functions have been removed:
           <UL>
           <LI> curve_is_between_cw()
           <LI> point_to_left()
           <LI> point_to_right()
           <LI> is_x_monotone()
           <LI> point_reflect_in_x_and_y()
           <LI> curve_reflect_in_x_and_y()
           <LI> do_intersect_to_right()
           <LI> do_intersect_to_left()
           </ul>

           Most functions, are required by the PlanarMapTraits_2 concept,
	   except for the make_x_monotone(), nearest_intersection_to_right(),
           nearest_intersection_to_left(), curves_overlap() and
	   curve_opposite(). PlanarMapWithIntersectionsTraits_2 requires all
	   these functions, except curve_opposite(), needed only by the
	   ArrangementTraits_2 concept.
           <p>
           Furthermore, the two functions curve_compare_at_x_left() and
           nearest_intersection_to_left() can be omitted, if the two functions
	   point_reflect_in_x() and curve_reflect_in_x() are implemented.
	   Reflection can be avoided, if the two _left functions are supplied.

        <LI> The type X_curve_2 of the PlanarMapWithIntersectionsTraits_2
           concept was renamed to X_monotone_curve_2, and the distinction
	   between this type and the Curve_2 type was made firm. The method
	   is_x_monotone() of the PlanarMapWithIntersectionsTraits_2 concept
	   was removed. The related method curve_make_x_monotone() is now
	   called for each input curve of type Curve_2 when curves are inserted
           into a Planar_map_with_intersections_2 to subdivide the input curve
	   into x-monotone sub-curves (and in case the curve is already
	   x-monotone, this function is responsible for casting it to an
	   x-monotone curve).

        <LI> New and improved traits classes:
           <LI> Conic traits - Arr_conic_traits_2
             Support finite segments of ellipses, hyperbolas and parabolas, as
	     well as line segments. The traits require an exact real number-
	     type, such as leda_real or CORE::Expr.

           <LI> Segment cached traits - Arr_segment_cached_traits_2
	     This class uses an improved representation for segments that helps
	     avoiding cascaded computations, thus achieving faster running
	     times. To work properly, an exact rational number-type should be
	     used.

           <LI> Polyline traits - Arr_polyline_traits_2
             The polyline traits class has been reimplemented to work in a more
	     efficient, generic manner. The new class replaces the obsolete
	     Arr_polyline_traits class. It is parameterized with a segment
	     traits class.

           <LI> Hyperbola and segment traits - Arr_hyper_segment_traits_2
             Supports line segments and segments of canonical hyperbolas.
	     This is the type of curves that arise when projecting segments
	     in three-space rotationally around a line onto a plane containing
	     the line. Such projections are often useful in CAD/CAM problems.

        <LI> Removed old traits class:
           <UL>
            <LI> The models of the PlanarMapWithIntersectionsTraits_2 concept
	      below became obsolete, as the new conic traits, namely
	      Arr_conic_traits_2, supports the same functionality and is much
	      more efficient.
              <UL>
                <LI> Arr_circles_real_traits
                <LI> Arr_segment_circle_traits
              </UL>
           <LI> The segment traits class and the new polyline traits class were
	      reimplemented using standard CGAL-kernel calls. This essentially
	      eliminated the corresponding leda traits classes, namely:
              <UL>
                <LI> Pm_leda_segment_traits_2
                <LI> Arr_leda_segment_traits_2
                <LI> Arr_leda_polyline_traits
              </UL>
              With the use of the Leda_rat_kernel new external package the same
	      functionality can be achieved with less overhead and more
	      efficiency.
      </UL>

<LI> Sweep Line<BR>
      <UL>
       <LI> The Sweep_line_2 package was reimplemented. As a consequence it is much
        more efficient, its traits is tighter (namely neither the two _left nor
	the reflection functions are required), and its interface has changed a
	bit.
        <OL>
          <LI> The following global functions have been removed:
            <UL>
             <LI> sweep_to_produce_subcurves_2()
             <LI> sweep_to_produce_points_2()
             <LI> sweep_to_construct_planar_map_2()
            </UL>
           Instead, the public methods of the Sweep_line_2 class listed below
	   were introduced:
           <UL>
             <LI> get_subcurves() - Given a container of curves, this function
	     returns a list of curves that are created by intersecting the
	     input curves.

             <LI> get_intersection_points() - Given a range of curves, this function
	     returns a list of points that are the intersection points of the
	     curves.

             <LI> get_intersecting_curves() - Given a range of curves, this function
	     returns an iterator to the beginning of a range that contains the
	     list of curves for each intersection point between any two curves
	     in the specified range.
           </UL>
        <LI> It is possible to construct a planar map with intersections (or an
	   arrangement) by inserting a range of curves into an empty map. This
	   will invoke the sweep-line process to construct the map more
	   efficiently.
       </OL>
      <LI> New interface functions to the Planar_map_with_intersections_2 class.
        The Planar_map_with_intersections_2 class maintains a planar map of
	input curves that possibly intersect each other and are not necessarily
	x-monotone. If an input curve, or a set of input curves, are known to
	be x-monotone and pairwise disjoint, the new functions below can be
	used to insert them into the map efficiently.
       </UL>
  </OL>
<LI> Polyhedral Surface<BR>
     <UL>
      <LI> The old design that was deprecated since CGAL 2.3 has been removed.
      <LI> Class <tt>Polyhedron_incremental_builder_3</tt>:
	 <UL>
	  <LI>Renamed local enum <tt>ABSOLUTE</tt> to
              <tt>ABSOLUTE_INDEXING</tt>, and <tt>RELATIVE</tt> to
              <tt>RELATIVE_INDEXING</tt> to avoid conflicts with similarly
              named macros of another library.
	  <LI>Changed member functions <tt>add_vertex()</tt>,
              <tt>begin_facet()</tt>, and <tt>end_facet()</tt> to return
              useful handles.
          <LI>Added <tt>test_facet()</tt> to check facets for validity
              before adding them.
          <LI>Added <tt>vertex( size_t i)</tt> to return <tt>Vertex_handle</tt>
              for index <tt>i</tt>.
	 </ul>
     </ul>

<LI> Halfedge Data Structure<BR>
     <UL>
      <LI> The old design that was deprecated since CGAL 2.3 has been removed.
     </UL>

</UL>

<H3>Support Library</H3>

<ul>
    <li> New container class Compact_container, which (roughly) provides the
      flexibility of std::list, with the memory compactness of std::vector.

    <li> Geomview_stream: added a function
      gv.draw_triangles(InputIterator begin, InputIterator end)
      which draws a set of triangles much more quickly than one by one.

    <li> Number types:
      <ul>
      <li> number types are now required to provide a function:
        std::pair&lt;double, double&gt;  to_interval(const NT &amp;).
      <li> number types are now required to provide mixed operators with "int".
      <li> CLN support removed.
      <li> faster square() for MP_Float.
      <li> added Gmp_q.
      </ul>

    <li> Qt_widget:
      <ul>
       <li> New classes:
        <ul>
	<li> Qt_help_window: provides a simple way to show some helpful
	  information about a demo as an HTML page.
	<li> Qt_widget_history: provides basic functionality to manipulate
	  intervals of Qt_widget class. The current visible area of Qt_widget
          is mapped to an interval. Each interval could be stored in the
	  Qt_widget_history object. So you can use this object to navigate in
          history.  It is mostly used by Qt_widget_standard_toolbar.
         </ul>
      <li> Changes:
        <ul>
	<li> Qt_widget_standard_toolbar: is derived from QToolBar class, so pay
	  attention to modify your code, if you used this class. Some public
	  methods were introduced to control the history object that the
          toolbar use to navigate.
	<li> the icons are now part of libCGALQt.
        </ul>
      <li> Deprecated members of Qt_widget:
        <ul>
        <li> add_to_history(), clear_history(), back(), forth(): use forward(),
          back() and clear_history() of the Qt_widget_standard_toolbar instead.
        <li> custom_redraw(): use redraw_on_back() and redraw_on_front() instead.
         </ul>
      <li> Optimizations:
        the output operators of the following classes have been optimized:
        <ul>
        <li> CGAL::Segment_2  (now tests for intersection with the drawing area)
        <li> CGAL::Triangle_2 (now tests for intersection with the drawing area)
        <li> CGAL::Triangulation_2 (is optimized for faster display on zooming)
        </ul>
      </ul>
</ul>

<p id="kernelerratum-3.0"><H3>Erratum in the Kernel manual</H3>

<ul>
<li> Intersection test routines
    <p>The documentation of
    CGAL::do_intersect
    should mention, for the 3D case:
    <br>
    Also, in three-dimensional space <i>Type1</i> can be
    <ul>
        <li>either
        <i>Plane_3&lt;Kernel&gt;</i>
        <li>or <i>Triangle_3&lt;Kernel&gt;</i>
    </ul>
    and <i>Type2</i> any of
    <ul>
        <li><i>Plane_3&lt;Kernel&gt;</i>
        <li><i>Line_3&lt;Kernel&gt;</i>
        <li><i>Ray_3&lt;Kernel&gt;</i>
        <li><i>Segment_3&lt;Kernel&gt;</i>
        <li><i>Triangle_3&lt;Kernel&gt;</i>
    </ul>

    <p>
    In the same way, for
    <i>Kernel::DoIntersect_3</i>:
    <br>
    for all pairs <i>Type1</i> and <i>Type2</i>, where
    the type <i>Type1</i> is
    <ul>
        <li>either
        <i>Kernel::Plane_3</i>
        <li>or <i>Kernel::Triangle_3</i>
    </ul>

    and <i>Type2</i> can be any of the following:
    <ul>
        <li><i>Kernel::Plane_3</i>
        <li><i>Kernel::Line_3</i>
        <li><i>Kernel::Ray_3</i>
        <li><i>Kernel::Segment_3</i>
        <li><i>Kernel::Triangle_3</i>
    </ul>

    <p>
    Philippe Guigue (I<small>NRIA</small> Sophia-Antipolis) should be
    mentioned as one of the authors.

</ul>

</DIV>

<h2 id="release2.4">Release 2.4</h2>
<DIV>
<p>Release date: May 2002</p>
<p>Version 2.4 differs from version 2.3 in the platforms that are supported and
in functionality.  There have also been a number of bug fixes for this release.</p>

<p>
Additional supported platforms:
<UL>
   <LI> Microsoft Visual C++, version 7.
   <LI> SunPro 5.3 (with patch 111685-05) on Solaris
   <LI> g++ 3.1 on Linux and Solaris
</UL>

<p>
The following functionality has been added or changed:<BR><BR>

<H3>Kernels</H3>

<UL>
   <LI> Point_d has been removed from the 2D and 3D kernels.  This type is
        now available from the d-dimensional kernel only.
</UL>

<H3>Basic Library</H3>

<UL>

  <LI> 2D Polygon Partitioning<BR>

      Traits requirements for optimal partitioning have been changed slightly.
     <BR><BR>

  <LI> 2D Sweep line<BR>

      A new package that implements a sweep-line algorithm to compute
      arrangements of curves for different families of curves, which are
      not necessarily line segments  (e.g., it also works for circular arcs).
      The resulting output can be the list of vertex points, the resulting
      subcurves or a planar map.
      <BR><BR>

  <LI>
       Planar Maps and

       Arrangements

  <UL>
  <LI> New quicker insertion functions of Planar_map_2 for cases where more
      precomputed information is available regarding the position of
      the inserted curve in the map.

  <LI> New query function for planar maps that determines whether a given
      point is within a given face of the planar map.

  <LI> New iterator over edges of planar maps in addition to the existing
      iterator over halfedges.

  <LI>  New copy constructor and assignment operator for arrangements.
  </UL>
  <BR><BR>

  <LI>
       Polyhedral Surface
  <UL>
  <LI>  new design introduced with release 2.3 now supported by VC7 compiler

  <LI>  Extended functionality of Polyhedron_incremental_builder:
        absolute indexing allows one to add new surfaces to existing ones.
  </UL>
  <BR><BR>

  <LI> 2D Triangulation
  <UL>
  <LI> There is a new triangulation data structure replacing the two
       previous ones. This new data structure is coherent with the 3d
       triangulation data structure and offer the advantages of both
       previous ones. Backward compatibility is ensured and this change
       is transparent for the user of triangulation classes.
  <LI> Constrained and Delaunay constrained triangulations are now able
       to handle intersecting input constraints.
       The behavior of constrained triangulations with repect to
       intersection of input constraints can be customized using
       an intersection tag.
  <LI> A new class Constrained_triangulation_plus offers a constrained
       hierarchy on top of a constrained triangulations. This additionnal
       data structure describes the subdivision of the original constraints
       into edges of the triangulations.
  </UL>
  <BR><BR>


  <LI> 3D Triangulation
   <UL>
   <LI> Running time improved by a better and more compact management of
        memory allocation

   <LI> Various improvements and small functionalities added:
     <UL>
     <LI> Triangulation_3&lt;GT,Tds&gt;::triangle() returns a triangle oriented
          towards the outside of the cell c for facet (c,i)
     <LI> New function insert(Point, Locate_type, Cell_handle, int, int)
          which avoids the location step.
     <LI> New function to get access to cells in conflict in a Delaunay
          insertion : find_conflicts() and insert_in_hole()
     <LI> New function TDS::delete_cells(begin, end).
     <LI> New functions : degree(v), reorient(), remove_decrease_dimension(),
          remove_from_simplex().
     </UL>

   <LI> Changes of interface:
     <UL>
     <LI> vertices and cells are the same for the triangulation data
          structure and the geometric triangulation
     <LI> the triangulation data structure uses Vertex_handle (resp
          Cell_handle) instead of Vertex* (resp Cell*).
     <LI> incident_cells() and incident_vertices() are templated by output
          iterators
     <LI> changes in the iterators and circulators interface:
        <UL>
        <LI> Iterators and circulators are convertible to handles
             automatically, no need to call "->handle()" anymore.
        <LI> Vertex_iterator split into All_vertices_iterator and
             Finite_vertices_iterator (and similar for cells...).
        <LI> TDS::Edge/Facet iterators now support operator->.
        </UL>
     </UL>
  </UL>
  <BR><BR>
  <LI> 2D Search structures<BR>
      Additional range search operations taking a predicate functor have been
      added
  </UL>

<H3>Support Library</H3>
<UL>
<LI>   Qt_widget
  <UL>
  <LI> We have added a new class for visualization of 2D CGAL objects.
       It is derived from Trolltech's Qt class QWidget and privdes a
       used to scale and pan.
  <LI> Some demos were developed for the following packages: 2D Alpha shapes,
       2D Convex Hull, Largest empty 2D rectangle, Maximum k-gon,
       Minimum ellipse,  Minimum 2D quadrilateral, 2D polygon partitioning
       2D regular and constrained triangulation.
  <LI> Tutorials are available to help users get used to Qt_widget
  </UL>
  <BR><BR>

<LI> Timer<BR>

     Fixed Timer class (for user process time) to have no wrap-around
     anymore on Posix-compliant systems.
</UL>

<p>
The following functionality is no longer supported:
<UL>
<LI> Planar maps of infinite curves (the so-called planar map bounding-box).
</UL>

<p>
Bugs in the following packages have been fixed:
   3D Convex hull, 2D Polygon partition, simple polygon generator

<p>
Also attempts have been made to assure compatability with the upcoming LEDA
release that introduces the leda namespace.

<p>
<H3>Known problems</H3>
<UL>
<LI> 2D Nef Polyhedra contains a memory leak.  Memory problems are also
     the likely cause of occasional run-time errors on some platforms.
<LI> The d-dimensional convex hull computation produces run-time errors on
     some platforms because of memory management bugs.
<LI> The new Halfedge Data Structure design introduced with release 2.3
     does not work on VC6.  See the release notes in the manual for more
     information.
<LI> The following deficiencies relate to planar maps, planar maps of
     intersecting curves (pmwx), arrangements and sweep line.
   <UL>
    <LI> On KCC, Borland and SunPro we guarantee neither compilation nor
         correct execution for all of the packages above.
    <LI> On VC6 and VC7 we guarantee neither compilation nor correct
         execution of the sweep line package.
    <LI> On CC (on Irix 6.5) the trapezoidal decomposition point location
         strategy is problematic when used with planar maps, pmwx, or
         arrangements (mind that this is the default for planar maps).
    <LI> On CC (on Irix 6.5) sweep line with polyline traits does not compile
         (mind that the so-called leda polyline traits does compile).
    <LI> On g++ (on Irix 6.5) the segment-circle (Arr_segment_circle_traits_2)
         traits does not compile for either of the above packages.
   </UL>
</UL>


</DIV>


<h2  id="release2.3">Release 2.3</h2>
<DIV>
<p>Release date: August 2001</p>

<p>Version 2.3 differs from version 2.2 in the platforms that are supported and
in functionality.</p>

<P>
Additional supported platform:

<UL>
   <LI> Gnu g++ 3.0 on Solaris and Linux
</UL>

<p>
The following functionality has been added:<BR><BR>

<H3>Kernels</H3>
<UL>
<LI> The 2D and 3D kernels now serve as models of the new kernel concept
     described in the recent paper, "An Adaptable and Extensible Geometry
     Kernel" by Susan Hert, Micheal Hoffmann, Lutz Kettner, Sylvain Pion,
     and Michael Seel to be presented at
     WAE 2001 (and
     soon available as a technical report).  This new kernel is
     completely compatible with the previous design but is more flexible
     in that it allows geometric predicates as well as objects to be easily
     exchanged and adapted individually to users' needs.

<LI> A new kernel called <TT>Simple_homogeneous</TT> is available. It is
     equivalent to <TT>Homogeneous</TT> but without reference-counted objects.

<LI> A new kernel called <TT>Filtered_kernel</TT> is available that allows
     one to build kernel traits classes that use exact and efficient predicates.

<LI> There are two classes, <TT>Cartesian_converter</TT> and
     <TT>Homogeneous_converter</TT>
     that allows one to convert objects between different Cartesian and
     homogeneous kernels, respectively.

<LI> A new d-dimensional kernel, <TT>Kernel_d</TT> is available.  It provides
     diverse kernel objects, predicates and constructions in d dimensions with
     two representations based on the kernel families <TT>Cartesean_d</TT> and
     <TT>Homogeneous_d</TT>
</UL>

<H3>Basic Library</H3>
   Almost all packages in the basic library have been adapted to the
   new kernel design to realize the flexibility this design makes possible.
   In several packages, this means that the traits class requirements have
   changed to conform to the function objects offered in the kernels so the
   kernels themselves can be used as traits classes in many instances.

<UL>
<LI>
    2D Convex Hull<BR>
    The traits requirements have changed slightly to bring them in line with
    the CGAL kernels.

<LI>
    3D Convex Hull
<UL>
  <LI> The function <TT>convex_hull_3</TT> now uses a new implementation of the
       quickhull algorithm and no longer requires LEDA.
  <LI> A new <TT>convex_hull_incremental_3</TT> function based on the new
       d-dimensional convex hull class is available for comparison purposes.
</UL><BR>

<LI>
     <TT>Convex_hull_d, Delaunay_d</TT><BR>
     Two new application classes offering the calculation of d-dimensional
     convex hulls and delaunay triangulations<BR><BR>

<LI>
     Polygons and Polygon Operations<BR>
     <UL>
       <LI> The traits class requirements have been changed.
       <LI> The simplicity test has a completely new implementation.
       <LI> Properties like convexity, simplicity and area can now be cached by
            polygons. You need to set a flag to select this behaviour.
     </UL>
     <BR>

     <BR><BR>
<LI>
     Planar Nef Polyhedra<BR>
     A new class (<TT>Nef_polyhedron_2</TT>) representing planar Nef polyhedra =
     rectilinearly bounded points sets that are the result of binary and
     topological operations starting from halfplanes.

     <BR><BR>
<LI> A new package offering functions to

     partition planar polygons into
     convex and y-monotone pieces is available.

     <BR><BR>
<LI>
     Planar Maps and

     Arrangements
     <UL>
     <LI> A new class <TT>Planar_map_with_intersections_2&lt;Planar_map&gt;</TT> for
          planar maps of possibly intersecting, possibly non-x-monotone,
          possibly overlapping curves (like <TT>Arrangement_2</TT> but without
          the hierarchy tree).

     <LI> I/O utilities for planar maps and arrangements for textual and
          graphical streams. (It is possible to save and later reload built
          planar maps or arrangements.)

     <LI> New arrangement traits class for line segments and circular arcs
          (<TT>Arr_segment_circle_traits&lt;NT&gt;</TT>).

     <LI> New faster traits for polylines specialized for using the LEDA
          rational kernel (<TT>Arr_leda_polylines_traits</TT>). The LEDA
          traits for segments was also made faster.

     <LI> A new point location strategy
          (<TT>Pm_simple_point_location&lt;Planar_map&gt;</TT>).
     </UL>
     <BR><BR>

<LI>
     Halfedge Data Structure<BR><BR>

     The halfedge data structure has been completely revised. The new design
     is more in line with the STL naming scheme and it provides a safe and
     coherent type system throughout the whole design (no void* pointers
     anymore), which allows for better extendibility. A user can add new
     incidences in the mesh easily. The new design also uses standard
     allocators with a new template parameter that has a suitable default.
     <BR><BR>

     The old design is still available, but its use is deprecated, see the
     manual of
     deprecated packages for its documentation. Reported bugs in
     copying the halfedge data structure (and therefore also polyhedral
     surfaces) have been fixed in both designs. Copying a list-based
     representation is now based on hash maps instead of std::map and is
     therefore considerably faster.

     <BR><BR>
<LI>
      Polyhedral Surface

     <BR><BR>
     The polyhedral surface has been rewritten to work with the new
     halfedge data structure design. The user level interface of the
     <TT>CGAL::Polyhedron_3</TT> class is almost backwards compatible with the
     previous class. The exceptions are the template parameter list,
     everything that relies on the flexibility of the underlying
     halfedge data structure, such as a self-written facet class, and
     that the distinction between supported normals and supported planes
     has been removed. Only planes are supported. See the manuals for
     suggestions how to handle normals instead of planes.

     <BR><BR>
     More example programs are provided with polyhedral surfaces,
     for example, one about Euler operator and one computing a subdivision
     surface given a control mesh as input.

     <BR><BR>
     The old design is still available for backwards compatibility and to
     support older compiler, such as MSVC++6.0. For the polyhedral surface,
     old and new design cannot be used simultaneously (they have identical
     include file names and class names). The include files select
     automatically the old design for MSVC++6.0 and the new design
     otherwise. This automatism can be overwritten by defining appropriate
     macros before the include files. The old design is selected with the
     <TT>CGAL_USE_POLYHEDRON_DESIGN_ONE</TT> macro. The new design is selected
     with the <TT>CGAL_USE_POLYHEDRON_DESIGN_TWO</TT> macro.

     <BR><BR>
<LI>
     2D Triangulation
     <UL>
     <LI> The geometric traits class requirements have been changed to conform
          to the new CGAL kernels.  CGAL kernel classes can be used as traits
          classes for all 2D triangulations except for regular triangulations.

     <LI> Additionnal functionality:
     <UL>
     <LI> dual method for regular triangulations (to build a power diagram)
     <LI> unified names and signatures for various "find_conflicts()"
          member functions in Delaunay and constrained Delaunay triangulation.
     <LI> As an alternative to the simple insert() member function,
          insertion of points in those triangulation can be performed using the
          combination of find_conflicts() and star_hole() which eventually
          allows the user to keep track of deleted faces.
     </UL>

     <LI> More demos and examples
     </UL>

     <BR>
<LI>
      3D Triangulation
     <UL>
     <LI> Major improvements
          <UL>
            <LI> A new class <TT>Triangulation_hierarchy_3</TT> that allows a
                 faster point location, and thus construction of the Delaunay
                 triangulation
            <LI> A new method for removing a vertex from a Delaunay
                 triangulation that solves all degenerate cases
            <LI> Running time of the usual location and insertion methods
                 improved
         </UL>

     <LI> A bit more functionality, such as
          <UL>
          <LI> New geomview output
          <LI> dual methods in Delaunay triangulations to draw the Voronoi
               diagram
          </UL>
     <LI> More demos and examples

     <LI> Changes in interface
          <UL>
          <LI> Traits classes requirements have been modified
          <LI> The kernel can be used directly as a traits class (except for
               regular triangulation)
          <LI> insert methods in <TT>Triangulation_data_structure</TT> have a
               new interface
          </UL>
     </UL>
     <BR>
<LI> A new class (<TT>Alpha_shapes_3</TT>) that computes Alpha shapes of point
     sets in 3D is available.

     <BR><BR>
<LI> The traits requirements for matrix search and
     minimum quadrilaterals have been changed to bring them
     in line with the CGAL kernels.
     <BR><BR>

<LI> Point_set_2
    <UL>
    <LI>  now independent of LEDA; based on the CGAL Delaunay triangulation
    <LI>  traits class requirements adapted to new kernel concept.
    <LI>  function template versions of the provided query operations are
          available
    </UL>
</UL>

<H3>Support Library</H3>
<UL>
<LI>  Number types:
      <UL>
       <LI> <TT>Lazy_exact_nt&lt;NT&gt;</TT> is a new number type wrapper to speed
            up exact number types.
       <LI> <TT>MP_Float</TT> is a new multiprecision floating point number
            type. It can do exact additions, subtractions and multiplications
            over floating point values.
      </UL>

<LI>  <TT>In_place_list</TT> has a new third template parameter
      (with a suitable default) for an STL-compliant allocator.

<LI>
      <TT>Unique_hash_map</TT> is a new support class.

<LI>
      <TT>Union_find</TT> is a new support class.

<LI>
     <TT>Geomview_stream</TT> :
    <UL>
    <LI> Geomview version 1.8.1 is now required.
    <LI> no need to have a <TT>~/.geomview</TT> file anymore.
    <LI> new output operators for triangulations.
    <LI> new output operators for <TT>Ray_2</TT>, <TT>Line_2</TT>,
         <TT>Ray_3</TT>, <TT>Line_3</TT>, <TT>Sphere_3</TT>.
    <LI> various new manipulators.
    </UL>

<LI> Window stream
    In cooperation with Algorithmic Solutions, GmBH (distributors of
    the LEDA library), we can now offer a visualization package
    downloadable in binary form that supports visualization on a ported
    version of the LEDA window lib.
</UL>

</DIV>


<h2 id="release2.2">Release 2.2</h2>
<DIV>
<p>Release date: October 2000</p>

<p>Version 2.2 differs from version 2.1 in the platforms that are supported and
in functionality.</p>

<P>
Additional supported platforms:

<UL>
   <LI> the KAI compiler (4.0) on Solaris 5.8
   <LI> Borland C++ (5.5)
</UL>

<p>
The following functionality has been added:

<UL>
<LI> There is a new, non-reference-counted kernel, Simple_cartesian. Because
     reference counting is not used, and thus coordinates are stored within a
     class, debugging is easier using this kernel.  This kernel can also be
     faster in some cases than the reference-counted Cartesian kernel.

<LI> New optimisation algorithms
     <UL>
        <LI> Min_annulus_d - Algorithm for computing the smallest enclosing
             annulus of points in arbitrary dimension
        <LI> Polytope_distance_d - Algorithm for computing the (squared)
             distance between two convex polytopes in arbitrary dimension
        <LI> Width_3 - Algorithm for computing the (squared) width of points
             sets in three dimensions
     </UL>

<LI> 2D Triangulations
     <UL>
       <LI> There are now two triangulation data structures available in CGAL.
            The new one uses a list to store the faces and allows one to
            represent two-dimensional triangulations embedded in three spaces
            as well as planar triangulations.
       <LI> The triangulation hierarchy which allows fast location query
            is now available.
     </UL>

<LI> Inifinite objects can now be included in planar maps.

<LI> Removal as well as insertions of vertices for 3D Delaunay triangulations
     is now possible.

<LI> A generator for ``random'' simple polygons is now available.

<LI> In directory demo/Robustness, programs that demonstrate typical robustness
     problems in geometric computing are presented along with the solutions to
     these problems that CGAL provides.
</UL>

<P>
The following functionality has been removed:
<UL>
  <LI> The binary operations on polygons (union, intersection ...) have been
       removed.  Those operations were not documented in the previous release
       (2.1).  Arrangements can often be used as a substitute.
</UL>
</DIV>


<h2  id="release2.1">Release 2.1</h2>

<DIV>
<p>Release date: January 2000</p>

<p>Version 2.1 differs from version 2.0 in the platforms that are supported and
in functionality.</p>

<p>
Supported platforms:

<UL>
   <LI> the newest gnu compiler (2.95.2) on Sun, SGI, Linux and Windows.
   <LI> the Microsoft Visual C++ compiler, version 6.
   <LI> the mips CC compiler version 7.3 under Irix.
</UL>

Support for the old g++ compiler (2.8) and for mips CC 7.2 has been dropped.

<BR><BR>
The following functionality has been added:

<UL>
<LI> Alpha shapes and weighted alpha shapes in 2D. Alpha shapes are a
     generalization of the convex hull of a point set.
<LI> Arrangements in 2D. Arrangements are related to and based on planar maps.
     The major difference between the two is that curves are allowed to
     intersect in the case of arrangements.
<LI> Extensions to triangulations in 2D.  Constrained triangulations are now
     dynamic: they support insertions of new constraint as well as removal of
     existing constraints.  There are also constrained Delaunay triangulations.
<LI> Triangulations in 3D were added, both Delaunay triangulations and regular
     triangulations.
<LI> Min_quadrilateral optimisations have been added.  These are algorithms to
     compute the minimum enclosing rectangle/parallelogram (arbitrary
     orientation) and the minimum enclosing strip of a convex point set.
<LI> 2d Point_set is a package for 2d range search operations, Delaunay
     triangulation, nearest neighbor queries. This package works only if
     LEDA
     is installed.
<LI> Support for GeoWin visualization library. This also depends on
     LEDA.
<LI> Support for using the
     CLN number type
     together with CGAL.
</LI>
</UL>
</DIV>


<h2 id="release2.0">Release 2.0</h2>
<DIV>
<p>Release date: June 1999</p>

<p>The main difference from release 1.2 is the
introduction of namespaces -- namespace <TT>std</TT> for code from
the standard library and namespace <TT>CGAL</TT> for
the CGAL library.
</DIV>


<h2 id="release1.2">Release 1.2</h2>
<DIV>
<p>Release date: January 1999</p>
<p>Additions to release 1.1 include: </p>

<UL>
   <LI>topological map
   <LI>planar map overlay
   <LI>regular and constrained triangulations
</UL>
</DIV>


<h2  id="release1.1">Release 1.1</h2>
<DIV>
<p>Release date: July 1998</p>

<p>Additions to release 1.0 include:
<UL>
   <LI>3D intersections </LI>
   <LI>kD points </LI>
   <LI>3D convex hull </LI>
   <LI>kD smallest enclosing sphere </LI>
</UL>
</DIV>



<h2 id="release1.0">Release 1.0</h2>
<DIV>
<p>Release date: April 1998</p>

<p>Additions to release 0.9 include:
<UL>
   <LI>Polyhedral surfaces </LI>
   <LI>Halfedge Data Structure</LI>
   <LI>Planar maps </LI>
</UL>
</DIV>


<h2 id="release0.9">Release 0.9</h2>
<DIV>
<p>Release date: June 1997</p>
<p>Initial (beta) release of the CGAL library.
</DIV>

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