derivative.h

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//------------------------------------------------------------------
//  
//   derivative.h
//  
//   Header file for the  Shift class and Derivative classes
//  
//   March 2001
//  
//   Kostas Orginos
//  
//------------------------------------------------------------------*/
#ifndef INCLUDED_DERIVATIVE_H
#define INCLUDED_DERIVATIVE_H
#include <stdio.h>
#include <util/data_types.h>
#include <util/site.h>

CPS_START_NAMESPACE

enum Dir {FRWD=+1,
          BKWD=-1 };

enum Quark {QUARK =+1,
            AQUARK=-1 };


class Shift
{
  int  d     ; // Forward or backward
  int  q     ; // Act on quark -> or on anti-quark <-

  bool more ; // Used to iterate over all possible shifts
public:
  Shift(){}
  Shift(int d_, int q_): d(d_),q(q_){}
  
  int D() const {return d;}
  int Q() const {return q;}
  Float sign(){return (Float)(d*q);} 

  int bit(){return -d*q;} 

  void Modify(int d_, int q_){d=d_;q=q_;}

  void Next() ;

  bool NotEnd(){return more ; }
  void Start(){q=QUARK;d=FRWD;more=true;}
  void NextQuark(){d-=2;more=(d>=-1);}


  //For debugging
  //void print(){printf("shift: d=%2i q=%2i | %4g\n",d,q,sign());}

  ~Shift(){}
};

class Derivative
{
  int* indx ;
  int Num ;

  bool more ;
  Shift* sh ;

  char *tag ;

  void Tag() ;

 public:
  Derivative():Num(0){Tag();}

  Derivative(int mu) ;

  Derivative(int mu,int nu) ;
  
  Derivative(int mu,int nu,int rho) ;

  Derivative(int *mu,int N) ;
  
  Derivative(const Derivative& tt) ;

  
  void Start() ;

  void Next() ;

  void NextQuark() ;

  bool NotEnd(){return more ; }

  void CalcEndPoints(int *aquark, int *quark, Site& s) ;

  void CalcListOfLinks(int *lnk) ;

  Float Fact() ;


  int DTermIndx() ;

  int N(){return Num;}

  void printTag(FILE *fp){fprintf(fp,"%s",tag);}

  // For debugging 
  //void sh_print(){for(int i(0);i<Num; i++) sh[i].print(); printf("\n"); }

  int NDTerms(){return 1<<Num ;}
  
  ~Derivative() ;

} ;

CPS_END_NAMESPACE

#endif // !INCLUDED_DERIVATIVE_H  

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