timestep.h

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#ifndef TIMESTEP_H
#define TIMESTEP_H
 
#include "utils/paramset.h"
#include "timebinmgr.h"
#include "timefac.h"
/*Flat array containing all active particles:
set in rebuild_activelist.*/
typedef struct ActiveParticles
{
    int64_t MaxActiveParticle;
    int64_t NumActiveParticle;
    int *ActiveParticle;
} ActiveParticles;
 
/* Structure to hold the kickfactors around the current position on the integer timeline*/
typedef struct
{
    /*Minimum and maximum active and occupied timebins. Initially (but never again) zero*/
    int mintimebin;
    int maxtimebin;
    /* Kick times per bin*/
    inttime_t Ti_kick[TIMEBINS+1];
    /* Drift time when this timebin was last active*/
    inttime_t Ti_lastactivedrift[TIMEBINS+1];
    /* Current drift time, which is universal.*/
    inttime_t Ti_Current;
    /* PM Timesteps*/
    inttime_t PM_length; 
    inttime_t PM_start;           /* current start point of the PM step*/
    inttime_t PM_kick;  /* current inttime of PM Kick (velocity) */
} DriftKickTimes;
 
int rebuild_activelist(ActiveParticles * act, const DriftKickTimes * const times, int NumCurrentTiStep, const double Time);
void free_activelist(ActiveParticles * act);
double get_atime(const inttime_t Ti_Current);
 
/* This function assigns new short-range timesteps to particles.
 * It will also advance the PM timestep and set the new timestep length.
 * Arguments:
 * ActiveParticles: particles to assign new timesteps for.
 * times: structure of kick times.
 * atime: current scale factor.
 * FastParticleType: particle type (generally neutrinos, 2) which has only long-range timestepping.
 * Cosmology: to compute hubble scaling factors.
 * asmth: size of PM smoothing cell in internal units. asmth = All.Asmth * PartManager->BoxSize / Nmesh
 * isFirstTimeStep: Flags to do special things for BHs on first time step.
 * Returns 0 if success, 1 if timestep is bad.*/
int find_timesteps(const ActiveParticles * act, DriftKickTimes * times, const double atime, int FastParticleType, const Cosmology * CP, const double asmth, const int isFirstTimeStep);
/* Apply half a kick to the particles: short-range and long-range.
 * These functions sync drift and kick times.*/
void apply_half_kick(const ActiveParticles * act, Cosmology * CP, DriftKickTimes * times, const double atime, const double MinEgySpec);
void apply_PM_half_kick(Cosmology * CP, DriftKickTimes * times);
 
int is_timebin_active(int i, inttime_t current);
 
inttime_t find_next_kick(inttime_t Ti_Current, int minTimeBin);
 
inttime_t init_timebins(double TimeInit);
 
/* Update the table of active bin drift times */
void update_lastactive_drift(DriftKickTimes * times);
 
DriftKickTimes init_driftkicktime(inttime_t Ti_Current);
 
int is_PM_timestep(const DriftKickTimes * const times);
 
void set_timestep_params(ParameterSet * ps);
 
#endif