Skeleton of HMC/Integrators

lib/qcd/QCD.h

@@ -413,5 +413,8 @@ namespace QCD {
 #include <qcd/utils/WilsonLoops.h>
 #include <qcd/utils/SUn.h>
 #include <qcd/action/Actions.h>
+#include <qcd/hmc/integrators/Integrator_base.h>
+#include <qcd/hmc/HMC.h>
+
 
 #endif

lib/qcd/hmc/HMC.cc

@@ -0,0 +1,98 @@
+#include <Grid.h>
+
+namespace Grid{
+  namespace QCD{
+
+    HMCparameters::HMCparameters(){
+	// FIXME fill this constructor  now just default values
+	  
+	////////////////////////////// Default values
+	Nsweeps             = 10;
+	TotalSweeps         = 10;
+	ThermalizationSteps = 0;
+	StartingConfig      = 0;
+	SaveInterval        = 1;
+	Filename_prefix     = "Conf_";
+	/////////////////////////////////
+	  
+      }
+
+
+    /////////////////////////////////////////////////////////////////
+
+    HybridMonteCarlo::HybridMonteCarlo(GridSerialRNG& R):RNG(R){
+	//FIXME
+      }
+
+
+    void HybridMonteCarlo::evolve(LatticeColourMatrix& Uin)const{
+      Real DeltaH;
+      Real timer;
+      
+      // Thermalizations
+      for(int iter=1; iter <= Params.ThermalizationSteps; ++iter){
+	std::cout << "-- # Thermalization step = "<< iter <<  "\n";
+	
+	DeltaH = evolve_step(Uin);
+	
+	std::cout<< "[Timing] Trajectory time (s) : "<< timer/1000.0 << "\n";
+	std::cout<< "dH = "<< DeltaH << "\n";
+	
+	// Update matrix
+	//Uin = md_->get_U();  //accept every time
+      }
+
+      // Actual updates
+      for(int iter=Params.StartingConfig; 
+	  iter < Params.Nsweeps+Params.StartingConfig; ++iter){
+	std::cout << "-- # Sweep = "<< iter <<  "\n";
+		
+	DeltaH = evolve_step(Uin);
+		
+	if(metropolis_test(DeltaH))  {};//Uin = md_->get_U();
+	// need sync?	
+      }
+
+      
+    }
+
+
+    RealD HybridMonteCarlo::evolve_step(LatticeColourMatrix& Uin)const{
+      /*
+      md_->init(Uin,RNG);     // set U and initialize P and phi's 
+      RealD H0 = md_->S();     // current state            
+      std::cout<<"Total H_before = "<< H0 << "\n";
+      
+      md_->integrator();
+      
+      RealD H1 = md_->calc_H();     // updated state            
+      std::cout<<"Total H_after = "<< H1 << "\n";
+      
+      return (H1-H0);
+      */
+      return 0;
+    }
+
+
+
+
+    bool HybridMonteCarlo::metropolis_test(const RealD DeltaH)const{
+      RealD rn_test;
+      RealD prob = std::exp(-DeltaH);
+      random(RNG,rn_test);
+      
+      std::cout<< "--------------------------------------------\n";
+      std::cout<< "dH = "<<DeltaH << "  Random = "<< rn_test 
+	       << "\nAcc. Probability = " << ((prob<1.0)? prob: 1.0)<< "   ";
+      
+      if((prob >1.0) || (rn_test <= prob)){       // accepted
+	std::cout <<"-- ACCEPTED\n";
+	return true;
+      } else {                               // rejected
+	std::cout <<"-- REJECTED\n";
+	return false;
+      }
+    }
+
+  }
+}

lib/qcd/hmc/HMC.h

@@ -0,0 +1,50 @@
+//--------------------------------------------------------------------
+/*! @file HMC.h
+ * @brief Declaration of classes for HybridMonteCarlo update
+ *
+ * @author Guido Cossu
+ */
+//--------------------------------------------------------------------
+#ifndef HMC_INCLUDED
+#define HMC_INCLUDED
+
+#include <string>
+#include <memory>
+
+namespace Grid{
+  namespace QCD{
+    
+    struct HMCparameters{
+      Integer Nsweeps; /* @brief Number of sweeps in this run */
+      Integer TotalSweeps; /* @brief If provided, the total number of sweeps */
+      Integer ThermalizationSteps;
+      Integer StartingConfig;
+      Integer SaveInterval; //Setting to 0 does not save configurations
+      std::string Filename_prefix; // To save configurations
+      
+      HMCparameters();
+    };
+    
+ 
+    class HybridMonteCarlo{
+      const HMCparameters Params;
+      GridSerialRNG& RNG; 
+      // FIXME need the integrator
+      
+      bool metropolis_test(const RealD DeltaH)const;
+      RealD evolve_step(LatticeColourMatrix&)const;
+      
+      
+    public:
+      HybridMonteCarlo(GridSerialRNG&);
+      ~HybridMonteCarlo(){};
+
+      void evolve(LatticeColourMatrix& Uin)const;
+
+    };
+    
+  }// QCD
+}// Grid
+
+
+#endif 

lib/qcd/hmc/integrators/Integrator_base.cc

@@ -0,0 +1,22 @@
+/*! 
+  @file Integrator_base.cc
+  @brief utilities for MD including funcs to generate initial HMC momentum
+ */
+
+
+#include <Grid.h>
+
+static const double sq3i = 1.0/sqrt(3.0);
+
+namespace Grid{
+  namespace QCD{
+
+    
+
+    void MDutils::generate_momenta_su3(LatticeColourMatrix& P,GridParallelRNG& pRNG){
+      SU3::GaussianLieAlgebraMatrix(pRNG, P);
+    }
+
+
+  }
+}

lib/qcd/hmc/integrators/Integrator_base.h

@@ -0,0 +1,50 @@
+//--------------------------------------------------------------------
+/*! @file Integrator_base.h
+ * @brief Declaration of classes for the abstract Molecular Dynamics integrator
+ *
+ * @author Guido Cossu
+ */
+//--------------------------------------------------------------------
+
+#ifndef INTEGRATOR_INCLUDED
+#define INTEGRATOR_INCLUDED
+
+class Action;
+class RandNum;
+class Observer;
+
+typedef std::vector<Action*> ActionLevel;
+typedef std::vector<ActionLevel> ActionSet;
+typedef std::vector<Observer*> ObserverList;
+
+/*! @brief Abstract base class for Molecular Dynamics management */
+
+namespace Grid{
+  namespace QCD{
+    
+    class Integrator{
+    private:
+      virtual void update_P(int lv,double ep) = 0;
+      virtual void update_U(double ep) = 0;
+      
+      virtual void register_observers() = 0;
+      virtual void notify_observers() = 0;
+      
+    public:
+      virtual ~Integrator(){}
+      virtual void init(const LatticeColourMatrix&,
+			const GridParallelRNG& RNG)=0;
+      virtual double S()const =0;
+      virtual void integrate(int level) =0;
+      virtual const LatticeColourMatrix get_U() const =0;
+      
+      void generate_momenta(LatticeColourMatrix& P,const RandNum& rand);
+    };
+    
+    namespace MDutils{
+      void generate_momenta_su3(LatticeColourMatrix& P,GridParallelRNG& RNG);
+    }
+    
+  }
+}
+#endif//INTEGRATOR_INCLUDED

lib/qcd/utils/SUn.h

@@ -543,6 +543,26 @@ Note that in step D setting B ~ X - A and using B in place of A in step E will g
     taExp(lie,out);
   }
 
+  static void GaussianLieAlgebraMatrix(GridParallelRNG     &pRNG,LatticeMatrix &out,double scale=1.0){
+    GridBase *grid = out._grid;
+    LatticeComplex ca (grid);
+    LatticeMatrix  lie(grid);
+    LatticeMatrix  la (grid);
+    Complex ci(0.0,scale);
+    Matrix ta;
+
+    out=zero;
+    for(int a=0;a<generators();a++){
+
+      gaussian(pRNG,ca); 
+      generator(a,ta);
+
+      la=ci*ca*ta;
+      out = lie+la; // e^{i la ta}
+    }
+  }
+
+
   static void HotConfiguration(GridParallelRNG &pRNG,LatticeGaugeField &out){
     LatticeMatrix Umu(out._grid);
     for(int mu=0;mu<Nd;mu++){