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126 lines
3.0 KiB
C++
126 lines
3.0 KiB
C++
//--------------------------------------------------------------------
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/*! @file HMC.h
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* @brief Declaration of classes for Hybrid Monte Carlo update
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*
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* @author Guido Cossu
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*/
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//--------------------------------------------------------------------
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#ifndef HMC_INCLUDED
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#define HMC_INCLUDED
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#include <string>
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#include <memory>
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namespace Grid{
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namespace QCD{
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struct HMCparameters{
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Integer Nsweeps; /* @brief Number of sweeps in this run */
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Integer TotalSweeps; /* @brief If provided, the total number of sweeps */
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Integer ThermalizationSteps;
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Integer StartingConfig;
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Integer SaveInterval; //Setting to 0 does not save configurations
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std::string Filename_prefix; // To save configurations
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HMCparameters();
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};
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template <class IntegType>
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class HybridMonteCarlo{
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const HMCparameters Params;
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GridSerialRNG sRNG;
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GridParallelRNG pRNG;
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Integrator<IntegType>& MD;
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bool metropolis_test(const RealD DeltaH){
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RealD rn_test;
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RealD prob = std::exp(-DeltaH);
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random(sRNG,rn_test);
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std::cout<< "--------------------------------------------\n";
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std::cout<< "dH = "<<DeltaH << " Random = "<< rn_test
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<< "\nAcc. Probability = " << ((prob<1.0)? prob: 1.0)<< " ";
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if((prob >1.0) || (rn_test <= prob)){ // accepted
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std::cout <<"-- ACCEPTED\n";
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return true;
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} else { // rejected
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std::cout <<"-- REJECTED\n";
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return false;
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}
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}
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RealD evolve_step(LatticeLorentzColourMatrix& U){
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MD.init(U,pRNG); // set U and initialize P and phi's
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RealD H0 = MD.S(U); // current state
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std::cout<<"Total H_before = "<< H0 << "\n";
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MD.integrate(U,0);
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RealD H1 = MD.S(U); // updated state
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std::cout<<"Total H_after = "<< H1 << "\n";
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return (H1-H0);
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}
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public:
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HybridMonteCarlo(HMCparameters Pms,
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Integrator<IntegType>& MolDyn,
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GridBase* grid):
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Params(Pms),MD(MolDyn),pRNG(grid){
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//FIXME
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// initialize RNGs
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sRNG.SeedRandomDevice();
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pRNG.SeedRandomDevice();
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}
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~HybridMonteCarlo(){};
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void evolve(LatticeLorentzColourMatrix& Uin){
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Real DeltaH;
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Real timer;
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// Thermalizations
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for(int iter=1; iter <= Params.ThermalizationSteps; ++iter){
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std::cout << "-- # Thermalization step = "<< iter << "\n";
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DeltaH = evolve_step(Uin);
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std::cout<< "[Timing] Trajectory time (s) : "<< timer/1000.0 << "\n";
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std::cout<< " dH = "<< DeltaH << "\n";
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// Update matrix
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//Uin = MD->get_U(); //accept every time
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}
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// Actual updates (evolve a copy Ucopy then copy back eventually)
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LatticeLorentzColourMatrix Ucopy(Uin._grid);
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for(int iter=Params.StartingConfig;
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iter < Params.Nsweeps+Params.StartingConfig; ++iter){
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std::cout << "-- # Sweep = "<< iter << "\n";
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Ucopy = Uin;
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DeltaH = evolve_step(Ucopy);
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if(metropolis_test(DeltaH)) Uin = Ucopy;
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// need sync?
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}
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}
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};
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}// QCD
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}// Grid
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#endif
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