pg_gaugeact.h

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// -*- C++ -*-
/*! \file
 *  \brief Parallelgram gauge action
 */
 
#ifndef __pg_gaugeact_h__
#define __pg_gaugeact_h__
 
#include "gaugeact.h"
#include "gaugebc.h"
 
namespace Chroma
{
 
  /*! @ingroup gaugeacts */
  namespace PgGaugeActEnv 
  { 
    extern const std::string name;
    bool registerAll();
  }
 
  // Parameter structure
  /*! @ingroup gaugeacts */
  struct PgGaugeActParams {
    // Base Constructor
    PgGaugeActParams();
    
    // Read params from some root path
    PgGaugeActParams(XMLReader& xml_in, const std::string& path);
 
    Real coeff;  
  };
  
  /*! @ingroup gaugeacts */
  void read(XMLReader& xml, const std::string& path, PgGaugeActParams& param);
  
 
  //! Parallelogram gauge action
  /*! \ingroup gaugeacts
   *
   * The standard parallelogram gauge action
   */
 
  class PgGaugeAct : public LinearGaugeAction
  {
  public:
    //! General CreateGaugeState
    PgGaugeAct(Handle< CreateGaugeState<P,Q> > cgs_, 
               const Real& coeff_) : 
      cgs(cgs_), coeff(coeff_) {}
 
    //! Read coeff from a param struct
    PgGaugeAct(Handle< CreateGaugeState<P,Q> > cgs_, 
               const PgGaugeActParams& p) :
      cgs(cgs_), coeff(p.coeff) {}
 
    //! Is anisotropy used?
    bool anisoP() const {return false;}
 
    //! Anisotropy factor
    const Real anisoFactor() const {return Real(1);}
 
    //! Anisotropic direction
    int tDir() const {return Nd-1;}
 
    //! Return the set on which the gauge action is defined
    /*! Defined on the even-off (red/black) set */
    const Set& getSet() const {return rb;}
 
    //! Compute staple
    /*! Default version. Derived class should override this if needed. */
    void staple(LatticeColorMatrix& result,
                const Handle< GaugeState<P,Q> >& state,
                int mu, int cb) const;
 
    //! Compute dS/dU
    void deriv(multi1d<LatticeColorMatrix>& result,
               const Handle< GaugeState<P,Q> >& state) const;
 
    //! Compute the actions
    Double S(const Handle< GaugeState<P,Q> >& state) const;
 
    //! Produce a gauge create state object
    const CreateGaugeState<P,Q>& getCreateState() const {return *cgs;}
 
    //! Destructor is automatic
    ~PgGaugeAct() {}
 
    // Accessors -- non mutable members.
    const Real getCoeff(void) const { return coeff; }
 
  protected:
    //! Partial constructor
    PgGaugeAct() {}
    //! Hide assignment
    void operator=(const PgGaugeAct& a) {}
 
  private:
    Handle< CreateGaugeState<P,Q> >  cgs;  // create gauge state
    Real coeff;              // The coupling coefficient
 
  };
 
}
 
 
#endif