ShallowWater1DComputeCFL.c

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#include <stdlib.h>
#include <basic.h>
#include <math.h>
#include <arrayfunctions.h>
#include <mathfunctions.h>
#include <physicalmodels/shallowwater1d.h>
#include <hypar.h>

double ShallowWater1DComputeCFL(
                                  void    *s, 
                                  void    *m, 
                                  double  dt, 
                                  double  t   
                               )
{
  HyPar           *solver = (HyPar*)   s;
  ShallowWater1D  *param  = (ShallowWater1D*) 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, v, c, dxinv, local_cfl;
    _ShallowWater1DGetFlowVar_((u+_MODEL_NVARS_*p),h,v);
    _GetCoordinate_(0,index[0],dim,ghosts,solver->dxinv,dxinv); /* 1/dx */
    c = sqrt(param->g*h); /* speed of gravity waves */
    local_cfl = (absolute(v)+c)*dt*dxinv; /* local cfl for this grid point */
    if (local_cfl > max_cfl) max_cfl = local_cfl;
    _ArrayIncrementIndex_(ndims,dim,index,done);
  }

  return(max_cfl);
}