mirror of
https://github.com/cosmo-sims/MUSIC.git
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8d9068852e
* added baryon staggering for SPH * added 2LPT for baryons/DM two-component fluid * cleaned up some code
85 lines
2 KiB
C++
85 lines
2 KiB
C++
/*
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transfer_bbks.cc - This file is part of MUSIC -
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a code to generate multi-scale initial conditions
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for cosmological simulations
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Copyright (C) 2010 Oliver Hahn
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*/
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#include "transfer_function.hh"
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//! Implementation of class TransferFunction_BBKS for the BBKS transfer function
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/*!
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This class implements the analytical fit to the matter transfer
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function by Bardeen, Bond, Kaiser & Szalay (BBKS).
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( see Bardeen et al. (1986) )
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*/
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class transfer_bbks_plugin : public transfer_function_plugin{
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private:
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double m_Gamma;
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public:
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//! Constructor
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/*!
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\param aCosm Structure of type Cosmology carrying the cosmological parameters
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\param bSugiyama flag whether the Sugiyama (1995) correction shall be applied (default=true)
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*/
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transfer_bbks_plugin( config_file& cf )
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: transfer_function_plugin( cf )
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{
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double Omega0 = cosmo_.Omega_m;
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double FreeGamma = -1.0;
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bool bSugiyama(true);
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try{
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bSugiyama= pcf_->getValue<bool>( "cosmology", "sugiyama_corr" );
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}catch(...){
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throw std::runtime_error("Error in \'tranfer_bbks_plugin\': need to specify \'[cosmology]/sugiyama_corr = [true/false]");
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}
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FreeGamma = pcf_->getValueSafe<double>( "cosmology", "gamma", FreeGamma );
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if( FreeGamma <= 0.0 ){
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m_Gamma = Omega0*0.01*cosmo_.H0;
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if( bSugiyama )
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m_Gamma *= exp(-cosmo_.Omega_b*(1.0+sqrt(2.0*0.01*cosmo_.H0)/Omega0));
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}else
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m_Gamma = FreeGamma;
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tf_distinct_ = false;
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tf_withvel_ = false;
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}
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//! computes the value of the BBKS transfer function for mode k (in h/Mpc)
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inline double compute( double k, tf_type type ){
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double q, f1, f2;
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if(k < 1e-7 )
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return 1.0;
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q = k/(m_Gamma);
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f1 = log(1.0 + 2.34*q)/(2.34*q);
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f2 = 1.0 + q*(3.89 + q*(259.21 + q*(162.771336 + q*2027.16958081)));
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return f1/sqrt(sqrt(f2));
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}
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inline double get_kmin( void ){
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return 1e-4;
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}
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inline double get_kmax( void ){
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return 1.e4;
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}
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};
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namespace{
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transfer_function_plugin_creator_concrete< transfer_bbks_plugin > creator("bbks");
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}
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