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/*@@
@file Courant.c
@date September 4 1999
@author Gabrielle Allen
@desc
Specification of timestep using Courant condition
@enddesc
@@*/
#include <stdlib.h>
#include <math.h>
#include "cctk.h"
#include "cctk_arguments.h"
#include "cctk_parameters.h"
void Time_Courant(CCTK_CARGUMENTS)
{
DECLARE_CCTK_PARAMETERS
DECLARE_CCTK_CARGUMENTS
CCTK_REAL min_spacing=0;
char *message;
/* Calculate the minimum grid spacing */
if (cctk_dim>=1)
{
min_spacing = cctk_delta_space[0];
}
if (cctk_dim>=2)
{
min_spacing = (min_spacing<cctk_delta_space[1] ?
min_spacing : cctk_delta_space[1]);
}
if (cctk_dim>=3)
{
min_spacing = (min_spacing<cctk_delta_space[2] ?
min_spacing : cctk_delta_space[2]);
}
if (cctk_dim>=4)
{
CCTK_WARN(0,"Time Step not defined for greater than 4 dimensions");
}
/* Calculate the courant timestep */
if (CCTK_Equals(courant_method,"courant_time"))
{
*courant_dt = courant_fac*(*courant_time)/sqrt((CCTK_REAL )cctk_dim);
}
else if (CCTK_Equals(courant_method,"courant"))
{
*courant_dt = courant_fac/(*courant_wave_speed)/sqrt((CCTK_REAL )cctk_dim);
}
/* Set the Cactus timestep */
if (! courant_outonly)
{
cctkGH->cctk_delta_time = *courant_dt;
message = (char *)malloc(1024*sizeof(char));
sprintf(message,"Time step set to %f",cctkGH->cctk_delta_time);
CCTK_INFO(message);
free(message);
}
else
{
cctkGH->cctk_delta_time = dtfac*min_spacing;
}
USE_CCTK_PARAMETERS
USE_CCTK_CARGUMENTS
}
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