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accel.c
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Fri, Oct 18, 14:13

accel.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <mpi.h>
#include "allvars.h"
#include "proto.h"
/*! \file accel.c
* \brief driver routine to carry out force computation
*/
/*! This routine computes the accelerations for all active particles.
* First, the long-range PM force is computed if the TreePM algorithm is
* used and a "big" PM step is done. Next, the gravitational tree forces
* are computed. This also constructs the tree, if needed.
*
* If gas particles are present, the density-loop for active SPH particles
* is carried out. This includes an iteration on the correct number of
* neighbours. Finally, the hydrodynamical forces are added.
*/
void compute_accelerations(int mode)
{
double tstart, tend;
#ifdef DETAILED_CPU
double t0,t1;
t0 = second();
#endif
if(ThisTask == 0)
{
printf("Start force computation...\n");
fflush(stdout);
}
#ifdef PMGRID
if(All.PM_Ti_endstep == All.Ti_Current)
{
tstart = second();
long_range_force();
tend = second();
All.CPU_PM += timediff(tstart, tend);
}
#endif
tstart = second(); /* measure the time for the full force computation */
gravity_tree(); /* computes gravity accel. */
if(All.TypeOfOpeningCriterion == 1 && All.Ti_Current == 0)
gravity_tree(); /* For the first timestep, we redo it
* to allow usage of relative opening
* criterion for consistent accuracy.
*/
tend = second();
All.CPU_Gravity += timediff(tstart, tend);
#ifdef FORCETEST
gravity_forcetest();
#endif
if(All.TotN_gas > 0)
{
if(ThisTask == 0)
{
printf("Start density computation...\n");
fflush(stdout);
}
#ifndef NO_DENSITY_FOR_GAS
tstart = second();
density(0); /* computes density, and pressure */
tend = second();
All.CPU_Hydro += timediff(tstart, tend);
tstart = second();
force_update_hmax(); /* tell the tree nodes the new SPH smoothing length such that they are guaranteed to hold the correct max(Hsml) */
tend = second();
All.CPU_Predict += timediff(tstart, tend);
#endif
#ifndef NO_HYDRO_FOR_GAS
if(ThisTask == 0)
{
printf("Start hydro-force computation...\n");
fflush(stdout);
}
tstart = second();
hydro_force(); /* adds hydrodynamical accelerations and computes viscous entropy injection */
tend = second();
All.CPU_Hydro += timediff(tstart, tend);
#endif
}
#ifdef AB_TURB
add_turb_accel();
#endif
if(ThisTask == 0)
{
printf("force computation done.\n");
fflush(stdout);
}
#ifdef DETAILED_CPU
t1 = second();
All.CPU_Accel += timediff(t0, t1);
#endif
}

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