##### https://github.com/geodynamics/citcoms
Tip revision: 4eaf0dc
Shape_functions.c
``````/*
*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
*
* CitcomS by Louis Moresi, Shijie Zhong, Lijie Han, Eh Tan,
* Clint Conrad, Michael Gurnis, and Eun-seo Choi.
* Copyright (C) 1994-2005, California Institute of Technology.
*
* This program is free software; you can redistribute it and/or modify
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*
*
*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
/*  Functions which construct the shape function values at all of the gauss
points in the element (including the reduced quadrature points). The element in question is
biquadratic in the velocities and therefore bilinear in the pressures.

To change elements it is necessary to change this file: Shape_functions.c,
and the element-data header file : element_definitions.h  but it should not be
necessary to change the main calculation/setup/solving machinery.		 */

#include <math.h>
#include "element_definitions.h"
#include "global_defs.h"

/*  =======================================================
Function creating shape_fn data in form of a structure
=======================================================*/

void construct_shape_functions(E)
struct All_variables *E;
{
double lpoly(),lpolydash();
int i,j,k,d,dd;
int remapj,remapk;

/* first zero ALL entries, even those not used in 2d. */

for(i=0;i<GNVI;i++)
{ E->N.vpt[i] = 0.0;
E->Nx.vpt[i] = 0.0;
E->Nx.vpt[GNVI+i] = 0.0;
E->Nx.vpt[2*GNVI+i] = 0.0;
}

for(i=0;i<GNPI;i++)
{ E->N.ppt[i] = 0.0;
E->Nx.ppt[i] = 0.0;
E->Nx.ppt[GNPI+i] = 0.0;
E->Nx.ppt[2*GNPI+i] = 0.0;
}

for(i=0;i<GN1VI;i++)
{ E->M.vpt[i] = 0.0;
E->Mx.vpt[i] = 0.0;
E->Mx.vpt[GN1VI+i] = 0.0;
}

for(i=0;i<GN1PI;i++)
{ E->M.ppt[i] = 0.0;
E->Mx.ppt[i] = 0.0;
E->Mx.ppt[GN1PI+i] = 0.0;
}

for(i=0;i<GN1VI;i++)
{ E->L.vpt[i] = 0.0;
E->Lx.vpt[i] = 0.0;
E->Lx.vpt[GN1VI+i] = 0.0;
}

for(i=0;i<GNVI;i++)
{ E->NM.vpt[i] = 0.0;
E->NMx.vpt[i] = 0.0;
E->NMx.vpt[GNVI+i] = 0.0;
E->NMx.vpt[2*GNVI+i] = 0.0;
}

for(i=1;i<=enodes[E->mesh.nsd];i++)   {
/*  for each node  */

for(j=1;j<=vpoints[E->mesh.nsd];j++)  {

/* for each integration point  */
E->N.vpt[GNVINDEX(i,j)] = 1.0;
for(d=1;d<=E->mesh.nsd;d++)
E->N.vpt[GNVINDEX(i,j)] *=
lpoly(bb[d-1][i],g_point[j].x[d-1]);

for(dd=1;dd<=E->mesh.nsd;dd++) {
E->Nx.vpt[GNVXINDEX(dd-1,i,j)] = lpolydash(bb[dd-1][i],g_point[j].x[dd-1]);
for(d=1;d<=E->mesh.nsd;d++)
if (d != dd)
E->Nx.vpt[GNVXINDEX(dd-1,i,j)] *= lpoly(bb[d-1][i],g_point[j].x[d-1]);
}
}

for(j=1;j<=ppoints[E->mesh.nsd];j++)  {
/* for each p-integration point  */
E->N.ppt[GNPINDEX(i,j)] = 1.0;
for(d=1;d<=E->mesh.nsd;d++)
E->N.ppt[GNPINDEX(i,j)] *=
lpoly(bb[d-1][i],p_point[j].x[d-1]);

for(dd=1;dd<=E->mesh.nsd;dd++) {
E->Nx.ppt[GNPXINDEX(dd-1,i,j)] = lpolydash(bb[dd-1][i],p_point[j].x[dd-1]);
for(d=1;d<=E->mesh.nsd;d++)
if (d != dd)
E->Nx.ppt[GNPXINDEX(dd-1,i,j)] *= lpoly(bb[d-1][i],p_point[j].x[d-1]);
}
}
}

for(j=1;j<=onedvpoints[E->mesh.nsd];j++)
for(k=1;k<=onedvpoints[E->mesh.nsd];k++)   {
E->M.vpt[GMVINDEX(j,k)] = 1.0;
for(d=1;d<=E->mesh.nsd-1;d++)
E->M.vpt[GMVINDEX(j,k)] *= lpoly(bb[d-1][j],s_point[k].x[d-1]);

for(dd=1;dd<=E->mesh.nsd-1;dd++) {
E->Mx.vpt[GMVXINDEX(dd-1,j,k)] = lpolydash(bb[dd-1][j],s_point[k].x[d-1]);
for(d=1;d<=E->mesh.nsd-1;d++)
if (d != dd)
E->Mx.vpt[GMVXINDEX(dd-1,j,k)] *= lpoly(bb[d-1][j],s_point[k].x[d-1]);
}
}

for(i=1;i<=enodes[E->mesh.nsd];i++)   {
for(j=1;j<=vpoints[E->mesh.nsd];j++)   {
/* for each integration point  */
E->NM.vpt[GNVINDEX(i,j)] = 1.0;
for(d=1;d<=E->mesh.nsd;d++)
E->NM.vpt[GNVINDEX(i,j)] *=
lpoly(bb[d-1][i],s_point[j].x[d-1]);

for(dd=1;dd<=E->mesh.nsd;dd++)                 {
E->NMx.vpt[GNVXINDEX(dd-1,i,j)] = lpolydash(bb[dd-1][i],s_point[j].x[dd-1]);
for(d=1;d<=E->mesh.nsd;d++)
if (d != dd)
E->NMx.vpt[GNVXINDEX(dd-1,i,j)] *= lpoly(bb[d-1][i],s_point[j].x[d-1]);

}
}

}

return; }

double lpoly(p,y)
int p;	   /*   selects lagrange polynomial , 1d: node p */
double y;  /*   coordinate in given direction to evaluate poly */
{
double value;

switch (p)
{
case 1:
value =0.5 * (1-y) ;
break;
case 2:
value =0.5 * (1+y) ;
break;
default:
value = 0.0;
}

return(value);
}

double lpolydash(p,y)
int p;
double y;
{
double value;
switch (p)
{
case 1:
value = -0.5 ;
break;
case 2:
value =  0.5 ;
break;
default:
value = 0.0;
}

return(value);	}

``````