void rtInitStep(double dt)
{
frt_real uDen = units->number_density;
frt_real uLen = units->length;
frt_real uTime = units->time;
frt_real dtCode = dt;
#ifdef COSMOLOGY
frt_real aExp = abox[min_level];
frt_real daExp = abox_from_tcode(tl[min_level]+dt) - abox[min_level];
frt_real HExp = Hubble(aExp)/units->time;
#else
frt_real aExp = 1.0;
frt_real daExp = 0.0;
frt_real HExp = 0.0;
#endif
start_time(WORK_TIMER);
frtCall(stepbegin)(&uDen,&uLen,&uTime,&aExp,&HExp,&daExp,&dtCode);
end_time(WORK_TIMER);
#ifdef RT_TRANSFER
rtInitStepTransfer();
#endif
rtUpdateTables();
#ifdef RT_DEBUG
switch(rt_debug.Mode)
{
case 1:
{
int i, cell;
cell = cell_find_position(rt_debug.Pos);
cart_debug("In cell-level debug for cell %d/%d",cell,cell_level(cell));
cart_debug("RT_HVAR_OFFSET: %d",RT_HVAR_OFFSET);
#ifdef RT_VAR_SOURCE
cart_debug("RT_VAR_SOURCE: %d",RT_VAR_SOURCE);
#endif
cart_debug("rt_grav_vars_offset: %d",rt_grav_vars_offset);
#ifdef RT_TRANSFER
cart_debug("rt_num_vars: %d",rt_num_vars);
#if (RT_TRANSFER_METHOD == RT_METHOD_OTVET)
cart_debug("RT_VAR_OT_FIELD: %d",RT_VAR_OT_FIELD);
cart_debug("rt_et_offset: %d",rt_et_offset);
cart_debug("rt_field_offset: %d",rt_field_offset);
#endif
#endif
for(i=0; i<num_vars; i++)
{
cart_debug("Var[%d] = %g",i,cell_var(cell,i));
}
break;
}
}
#endif /* RT_DEBUG */
}
void compute_time_scalefactor_spline(){
double aexp_ini, aexp_end, da, integrand;
double *tt, *aa;
int nsteps;
// Initialize
nsteps = 5000;
aexp_ini = sim._aexp_ini/2.0;
aexp_end = 2.0;
da = (aexp_end - aexp_ini)/double(nsteps-1);
tt = new double[nsteps];
aa = new double[nsteps];
for(int i = 0; i < nsteps; i++) {
tt[i] = 0.0;
aa[i] = aexp_ini + da*i;
}
// Integrate up
for(int i = 1; i < nsteps; i++){
integrand = da/( Hubble(aa[i]) * pow3(aa[i]) );
tt[i] = tt[i-1] + integrand;
}
// Shift to tt=0 for a = 0 (just for consistency)
int aunityind = int( (1.0 - aexp_ini) / da + 0.5 );
double t0 = tt[aunityind];
for(int i = 0; i < nsteps; i++)
tt[i] -= t0;
// Make a spline
sim._ttofa_spline = DSpline(aa, tt, nsteps, "The tt(a) function");
sim._aoftt_spline = DSpline(tt, aa, nsteps, "The a(tt) function");
delete[] aa;
delete[] tt;
}
double calc_new_timestep(){
double dt1, dt2, dt3, dt, cfac = 0.1;
double rhomax = 0.0, vmax = 0.0;
// Maximim density
#ifdef OMP
#pragma omp parallel for reduction(max:rhomax)
#endif
for(int i = 0;i < sim._ngrid_tot; i++)
if(sim._Rho[i] > rhomax)
rhomax = sim._Rho[i];
// Maximum velocity
#ifdef OMP
#pragma omp parallel for reduction(max:vmax)
#endif
for(int i = 0;i < sim._npart; i++)
for(int k = 0; k < 3; k++)
if(fabs(sim._Particle[i]._v[k]) > vmax)
vmax = fabs(sim._Particle[i]._v[k]);
// dt based gravity free fall time
dt1 = cfac * sqrt(pow2(M_PI)/(4.0 * sim._omega_m * sim._aexp * rhomax));
// dt based on background expansion
dt2 = 0.1/(sim._aexp*Hubble(sim._aexp));
// dt based on courant condition for max velocity (do not allow travel more than 1/2 gridcell)
dt3 = cfac/(double(sim._ngrid) * vmax);
// Take the minimum time-step
dt = min(dt1,dt2);
dt = min(dt,dt3);
return dt;
}
