driftfac.h

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/*******************************************************************************
 * \copyright   This file is part of the GADGET4 N-body/SPH code developed
 * \copyright   by Volker Springel. Copyright (C) 2014-2020 by Volker Springel
 * \copyright   (vspringel@mpa-garching.mpg.de) and all contributing authors.
 *******************************************************************************/
 
#ifndef DRIFTFAC_H
#define DRIFTFAC_H
 
#include <gsl/gsl_integration.h>
#include <gsl/gsl_math.h>
#include <math.h>
#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include "../data/dtypes.h"
#include "../main/main.h"
#include "gadgetconfig.h"
 
class driftfac
{
 public:
  void init_drift_table(void);
  double get_drift_factor(integertime time0, integertime time1);
  double get_gravkick_factor(integertime time0, integertime time1);
  double get_hydrokick_factor(integertime time0, integertime time1);
  double get_comoving_distance(integertime time0);
  double get_comoving_distance_for_scalefactor(double ascale);
  double get_scalefactor_for_comoving_distance(double dist);
  integertime get_gravkick_factor_inverse(double fac);
 
  static double hubble_function(double a)
  {
    double hubble_a = All.Omega0 / (a * a * a) + (1 - All.Omega0 - All.OmegaLambda) / (a * a) + All.OmegaLambda;
 
    hubble_a = All.Hubble * sqrt(hubble_a);
 
    return hubble_a;
  }
 
 private:
#define DRIFT_TABLE_LENGTH 1000
 
  double DriftTable[DRIFT_TABLE_LENGTH];
 
  double GravKickTable[DRIFT_TABLE_LENGTH];
 
  double HydroKickTable[DRIFT_TABLE_LENGTH];
 
  double logTimeBegin;
  double logTimeMax;
 
  static double drift_integ(double a, void *param)
  {
    double h = hubble_function(a);
 
    return 1 / (h * a * a * a);
  }
 
  static double gravkick_integ(double a, void *param)
  {
    double h = hubble_function(a);
 
    return 1 / (h * a * a);
  }
 
  static double hydrokick_integ(double a, void *param)
  {
    double h = hubble_function(a);
 
    return 1 / (h * pow(a, 3 * GAMMA_MINUS1) * a);
  }
};
 
extern driftfac Driftfac;
 
#endif