sph_particle_data.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 SPHPARTDATA_H
#define SPHPARTDATA_H
 
#include "../data/constants.h"
#include "../data/dtypes.h"
#include "../data/intposconvert.h"
#include "../data/macros.h"
#include "../data/mymalloc.h"
#include "../mpi_utils/setcomm.h"
#include "../system/system.h"
#include "../time_integration/timestep.h"
 
/* in this structure, all SPH variables are put that are needed for passive
 * particles in the hydro force calculation. Only this part will be sent
 * to other nodes if needed
 */
struct sph_particle_data_hydrocore
{
  MyFloat Hsml;               
  MyFloat DhsmlDensityFactor; 
  MyFloat VelPred[3];         
  MyFloat DivVel;  
  MyFloat CurlVel; 
  MyFloat Csnd;
 
  MyFloat Density;  
  MyFloat Pressure; 
#ifdef TIMEDEP_ART_VISC
  MyFloat Alpha; 
#endif
#ifdef PRESSURE_ENTROPY_SPH
  MyFloat EntropyToInvGammaPred;     
  MyFloat DhsmlDerivedDensityFactor; 
  MyFloat PressureSphDensity;        /* current density derived from the pressure estimate */
#endif
};
 
struct sph_particle_data : public sph_particle_data_hydrocore
{
  MyFloat Entropy;     
  MyFloat EntropyPred; 
  MyFloat HydroAccel[3]; 
#ifdef HIERARCHICAL_GRAVITY
  MyFloat FullGravAccel[3]; 
#endif
  MyFloat DtEntropy; 
  MyFloat DtDensity; 
  MyFloat DtHsml;    
  MyFloat NumNgb; 
  MyFloat Rot[3]; 
  MyFloat MaxSignalVel; 
  MyFloat CurrentMaxTiStep;
 
#ifdef PRESSURE_ENTROPY_SPH
  MyFloat
      DtPressureSphDensity; 
#endif
 
#ifdef TIMEDEP_ART_VISC
  MyFloat DivVelOld; /* local velocity gradient from the previous time step */
  MyFloat decayVel;  /* decay velocity for the viscosity parameter */
#endif
 
#ifdef IMPROVED_VELOCITY_GRADIENTS
  struct
  {
    MyFloat dx_dx;
    MyFloat dx_dy;
    MyFloat dx_dz;
    MyFloat dy_dy;
    MyFloat dy_dz;
    MyFloat dz_dz;
  } dpos; /* contains the matrix elements needed for the improved gradient estimate */
 
  MyFloat dvel[NUMDIMS][NUMDIMS]; /* contains the velocity gradients */
#endif
 
#ifdef STARFORMATION
  MyFloat Metallicity;
  MyFloat MassMetallicity;
#endif
 
#ifdef COOLING
  MyFloat Ne; 
#endif
 
#ifdef OUTPUT_COOLHEAT
  MyFloat CoolHeat;
#endif
 
#ifdef STARFORMATION
  MyFloat Sfr;
#endif
 
  inline MyFloat get_sound_speed(void)
  {
    MyFloat csnd;
 
    if(Density > 0)
      csnd = sqrt(static_cast<MyReal>(GAMMA) * Pressure / Density);
    else
      csnd = 0;
 
    return csnd;
  }
 
  /* compute the pressure of particle i */
  inline MyFloat get_pressure(void)
  {
#ifndef PRESSURE_ENTROPY_SPH
    return EntropyPred * pow(Density, (MyFloat)GAMMA);
#else
    return pow(EntropyToInvGammaPred * PressureSphDensity, GAMMA);
#endif
  }
 
  inline void set_thermodynamic_variables(void)
  {
    Pressure = get_pressure();
 
    if(Pressure < 0)
      Terminate("Pressure=%g  rho=%g  entr=%g entrpred=%g\n", Pressure, Density, Entropy, EntropyPred);
 
    Csnd = get_sound_speed();
  }
 
  inline MyFloat get_Hsml() { return Hsml; }
 
#ifdef IMPROVED_VELOCITY_GRADIENTS
  void set_velocity_gradients(void);
#endif
 
#ifdef TIMEDEP_ART_VISC
  void set_viscosity_coefficient(double dt);
#endif
};
 
#endif