ShallowWater2DComputeCFL.c

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#include <stdlib.h>
#include <basic.h>
#include <math.h>
#include <arrayfunctions.h>
#include <mathfunctions.h>
#include <physicalmodels/shallowwater2d.h>
#include <hypar.h>

double ShallowWater2DComputeCFL(
                                  void    *s, 
                                  void    *m, 
                                  double  dt, 
                                  double  t   
                               )
{
  HyPar           *solver = (HyPar*)   s;
  ShallowWater2D  *param  = (ShallowWater2D*) solver->physics;

  int *dim    = solver->dim_local;
  int ghosts  = solver->ghosts;
  int ndims   = solver->ndims;
  int index[ndims];
  double *u   = solver->u;

  double max_cfl = 0;
  int done = 0; _ArraySetValue_(index,ndims,0);
  while (!done) {
    int p; _ArrayIndex1D_(ndims,dim,index,ghosts,p);
    double h, uvel, vvel, c, dxinv, dyinv, local_cfl[_MODEL_NDIMS_];
    _ShallowWater2DGetFlowVar_((u+_MODEL_NVARS_*p),h,uvel,vvel);

    _GetCoordinate_(_XDIR_,index[_XDIR_],dim,ghosts,solver->dxinv,dxinv); /* 1/dx */
    _GetCoordinate_(_YDIR_,index[_YDIR_],dim,ghosts,solver->dxinv,dyinv); /* 1/dy */
    c = sqrt(param->g*h); /* speed of gravity waves */
    local_cfl[_XDIR_]=(absolute(uvel)+c)*dt*dxinv;/* local cfl for this grid point (x) */
    local_cfl[_YDIR_]=(absolute(vvel)+c)*dt*dyinv;/* local cfl for this grid point (y) */
    if (local_cfl[_XDIR_] > max_cfl) max_cfl = local_cfl[_XDIR_];
    if (local_cfl[_YDIR_] > max_cfl) max_cfl = local_cfl[_YDIR_];

    _ArrayIncrementIndex_(ndims,dim,index,done);
  }

  return(max_cfl);
}