// @(#)root/quadp:$Name:  $:$Id: TQpSolverBase.h,v 1.2 2004/05/24 12:45:40 brun Exp $
// Author: Eddy Offermann   May 2004

/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

/*************************************************************************
 * Parts of this file are copied from the OOQP distribution and          *
 * are subject to the following license:                                 *
 *                                                                       *
 * COPYRIGHT 2001 UNIVERSITY OF CHICAGO                                  *
 *                                                                       *
 * The copyright holder hereby grants you royalty-free rights to use,    *
 * reproduce, prepare derivative works, and to redistribute this software*
 * to others, provided that any changes are clearly documented. This     *
 * software was authored by:                                             *
 *                                                                       *
 *   E. MICHAEL GERTZ      gertz@mcs.anl.gov                             *
 *   Mathematics and Computer Science Division                           *
 *   Argonne National Laboratory                                         *
 *   9700 S. Cass Avenue                                                 *
 *   Argonne, IL 60439-4844                                              *
 *                                                                       *
 *   STEPHEN J. WRIGHT     swright@cs.wisc.edu                           *
 *   Computer Sciences Department                                        *
 *   University of Wisconsin                                             *
 *   1210 West Dayton Street                                             *
 *   Madison, WI 53706   FAX: (608)262-9777                              *
 *                                                                       *
 * Any questions or comments may be directed to one of the authors.      *
 *                                                                       *
 * ARGONNE NATIONAL LABORATORY (ANL), WITH FACILITIES IN THE STATES OF   *
 * ILLINOIS AND IDAHO, IS OWNED BY THE UNITED STATES GOVERNMENT, AND     *
 * OPERATED BY THE UNIVERSITY OF CHICAGO UNDER PROVISION OF A CONTRACT   *
 * WITH THE DEPARTMENT OF ENERGY.                                        *
 *************************************************************************/

#ifndef ROOT_TQpSolverBase
#define ROOT_TQpSolverBase

#ifndef ROOT_TROOT
#include "TROOT.h"
#endif
#ifndef ROOT_TClass
#include "TClass.h"
#endif
#ifndef ROOT_TError
#include "TError.h"
#endif
#ifndef ROOT_TMath
#include "TMath.h"
#endif

#ifndef ROOT_TQpVar
#include "TQpVar.h"
#endif
#ifndef ROOT_TQpDataBase
#include "TQpDataBase.h"
#endif
#ifndef ROOT_TQpResidual
#include "TQpResidual.h"
#endif
#ifndef ROOT_TQpProbBase 
#include "TQpProbBase.h" 
#endif
#ifndef ROOT_TQpLinSolverBase 
#include "TQpLinSolverBase.h" 
#endif

#ifndef ROOT_TMatrixD
#include "TMatrixD.h"
#endif

///////////////////////////////////////////////////////////////////////////
//                                                                       //
// Abstract base class for QP solver using interior-point                //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

enum ETerminationCode
{
  kSUCCESSFUL_TERMINATION = 0,
  kNOT_FINISHED,
  kMAX_ITS_EXCEEDED,
  kINFEASIBLE,
  kUNKNOWN
};

class TQpSolverBase : public TObject {

protected:
  TQpLinSolverBase *fSys;

  Double_t          fDnorm;          // norm of problem data

  Double_t          fMutol;          // termination parameters
  Double_t          fArtol;

  Double_t          fGamma_f;        // parameters associated with the step length heuristic
  Double_t          fGamma_a;
  Double_t          fPhi;            // merit function, defined as the sum of the complementarity gap
                                     // the residual norms, divided by (1+norm of problem data)
  Int_t             fMaxit;          // maximum number of  iterations allowed

  Double_t         *fMu_history;     //[fMaxit] history of values of mu obtained on all iterations to date
  Double_t         *fRnorm_history;  //[fMaxit] history of values of residual norm obtained on all iterations to date
  Double_t         *fPhi_history;    //[fMaxit] history of values of phi obtained on all iterations to date

  Double_t         *fPhi_min_history;//[fMaxit] the i-th entry of this array contains the minimum value of phi
                                     //          encountered by the algorithm on or before iteration i

public:
  Int_t             fIter;           // iteration counter

  TQpSolverBase();
  TQpSolverBase(const TQpSolverBase &another);

  virtual ~TQpSolverBase();

  virtual void     Start       (TQpProbBase *formulation,             // starting point heuristic
                                TQpVar *iterate,TQpDataBase *prob,
                                TQpResidual *resid,TQpVar *step);
  virtual void     DefStart    (TQpProbBase *formulation,             // default starting point heuristic
                                TQpVar *iterate,TQpDataBase *prob,
                                TQpResidual *resid,TQpVar *step);
  virtual void     SteveStart  (TQpProbBase *formulation,             // alternative starting point heuristic
                                TQpVar *iterate,TQpDataBase *prob,
                                TQpResidual *resid,TQpVar *step);
  virtual void     DumbStart   (TQpProbBase *formulation,             // alternative starting point heuristic: sets the
                                TQpVar *iterate,TQpDataBase *prob,    // "complementary" variables to a large positive value
                                TQpResidual *resid,TQpVar *step);     // (based on the norm of the problem data) and the
                                                                      // remaining variables to zero

  virtual Int_t    Solve       (TQpDataBase *prob,TQpVar *iterate,    // implements the interior-point method for solving the QP
                                TQpResidual *resids) = 0;

  virtual Double_t FinalStepLength
                               (TQpVar *iterate,TQpVar *step);        // Mehrotra's heuristic to calculate the final step

  virtual void     DoMonitor   (TQpDataBase *data,TQpVar *vars,       // perform monitor operation at each interior-point
                                TQpResidual *resids,Double_t alpha,   // iteration
                                Double_t sigma,Int_t i,Double_t mu,
                                Int_t stop_code,Int_t level);
  virtual void     DefMonitor  (TQpDataBase *data,TQpVar *vars,       // default monitor: prints out one line of information
                                TQpResidual *resids,Double_t alpha,      // on each interior-point iteration
                                Double_t sigma,Int_t i,Double_t mu,
                                Int_t stop_code,Int_t level) = 0;
  virtual Int_t    DoStatus    (TQpDataBase *data,TQpVar *vars,       // this method called to test for convergence status at
                                TQpResidual *resids,Int_t i,Double_t mu, // at the end of each interior-point iteration
                                Int_t level);
  virtual Int_t    DefStatus   (TQpDataBase *data,TQpVar *vars,       // default method for checking status. May be replaced
                                TQpResidual *resids,Int_t i,Double_t mu, // by a user-defined method
                                Int_t level);

  TQpLinSolverBase *GetLinearSystem()            { return fSys; }
  void              SetMuTol       (Double_t m)  { fMutol = m; }
  Double_t          GetMuTol       ()            { return fMutol; }

  void              SetArTol       (Double_t ar) { fArtol = ar; }
  Double_t          GetArTol       ()            { return fArtol; }
  Double_t          DataNorm       ()            { return fDnorm; }

  TQpSolverBase &operator= (const TQpSolverBase &source);

  ClassDef(TQpSolverBase,1) // Qp Solver class
};

#endif