global_metropolis_accrej.cc

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/*! \file
 * \brief Simple metropolis accept/reject
 *
 * Simple metropolis accept/reject
 */
 
#include "chromabase.h"
#include "update/molecdyn/hmc/global_metropolis_accrej.h"
 
namespace Chroma { 
 
  // Metropolis accept/reject
  /*! @ingroup hmc */
  bool globalMetropolisAcceptReject(const Double& DeltaH) 
  { 
    START_CODE();
 
    // If deltaH is negative then always accept
    bool ret_val;
    
    
    if ( toBool( DeltaH <= Double(0)) ) {
      ret_val = true;
    }
    else {
      Double AccProb = exp(-DeltaH);
      Double uni_dev;
      random(uni_dev);
      
      
      if( toBool( uni_dev <= AccProb ) ) { 
        
        ret_val = true;
        
      }
      else {    
        
        ret_val = false;
      }
    }
    
    END_CODE();
 
    return ret_val;
  }  
 
} // End namespace