gauge_field.h

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#ifndef _GAUGE_QUDA_H
#define _GAUGE_QUDA_H

#include <quda_internal.h>
#include <quda.h>
#include <lattice_field.h>

namespace quda {

  struct GaugeFieldParam : public LatticeFieldParam {
    int nColor;
    int nFace;

    QudaReconstructType reconstruct;
    QudaGaugeFieldOrder order;
    QudaGaugeFixed fixed;
    QudaLinkType link_type;
    QudaTboundary t_boundary;

    double anisotropy;
    double tadpole;
    double scale;

    void *gauge; // used when we use a reference to an external field

    QudaFieldCreate create; // used to determine the type of field created

    QudaFieldGeometry geometry; // whether the field is a scale, vector or tensor
    int pinned; //used in cpu field only, where the host memory is pinned

    // whether we need to compute the fat link maxima
    // FIXME temporary flag until we have a kernel that can do this, then we just do this in copy()
    // always set to false, requires external override
    bool compute_fat_link_max; 

    int r[QUDA_MAX_DIM];

    QudaGhostExchange ghostExchange;

    QudaStaggeredPhase staggeredPhaseType;

    bool staggeredPhaseApplied;

    // Default constructor
  GaugeFieldParam(void* const h_gauge=NULL) : LatticeFieldParam(),
      nColor(3),
      nFace(0),
      reconstruct(QUDA_RECONSTRUCT_NO),
      order(QUDA_INVALID_GAUGE_ORDER),
      fixed(QUDA_GAUGE_FIXED_NO),
      link_type(QUDA_WILSON_LINKS),
      t_boundary(QUDA_INVALID_T_BOUNDARY),
      anisotropy(1.0),
      tadpole(1.0),
      scale(1.0),
      gauge(h_gauge),
      create(QUDA_REFERENCE_FIELD_CREATE), 
      geometry(QUDA_VECTOR_GEOMETRY),
      pinned(0),
      compute_fat_link_max(false),
      ghostExchange(QUDA_GHOST_EXCHANGE_PAD),

      staggeredPhaseType(QUDA_INVALID_STAGGERED_PHASE),
      staggeredPhaseApplied(false)
        {
          // variables declared in LatticeFieldParam
          precision = QUDA_INVALID_PRECISION;
          nDim = 4;
          pad  = 0;
          for(int dir=0; dir<nDim; ++dir) {
            x[dir] = 0;
            r[dir] = 0;
          }
        }
        
  GaugeFieldParam(const int *x, const QudaPrecision precision, const QudaReconstructType reconstruct,
                  const int pad, const QudaFieldGeometry geometry, 
                  const QudaGhostExchange ghostExchange=QUDA_GHOST_EXCHANGE_PAD) 
    : LatticeFieldParam(), nColor(3), nFace(0), reconstruct(reconstruct), 
        order(QUDA_INVALID_GAUGE_ORDER), fixed(QUDA_GAUGE_FIXED_NO), 
        link_type(QUDA_WILSON_LINKS), t_boundary(QUDA_INVALID_T_BOUNDARY), anisotropy(1.0), 
        tadpole(1.0), scale(1.0), gauge(0), create(QUDA_NULL_FIELD_CREATE), geometry(geometry), 
        pinned(0), compute_fat_link_max(false), ghostExchange(ghostExchange), 
        staggeredPhaseType(QUDA_INVALID_STAGGERED_PHASE), staggeredPhaseApplied(false)
        {
          // variables declared in LatticeFieldParam
          this->precision = precision;
          this->nDim = 4;
          this->pad = pad;
          for(int dir=0; dir<nDim; ++dir) {
            this->x[dir] = x[dir];
            this->r[dir] = 0;
          }
        }
      
  GaugeFieldParam(void *h_gauge, const QudaGaugeParam &param) : LatticeFieldParam(param),
      nColor(3), nFace(0), reconstruct(QUDA_RECONSTRUCT_NO), order(param.gauge_order), 
        fixed(param.gauge_fix), link_type(param.type), t_boundary(param.t_boundary), 
        anisotropy(param.anisotropy), tadpole(param.tadpole_coeff), scale(param.scale), gauge(h_gauge), 
        create(QUDA_REFERENCE_FIELD_CREATE), geometry(QUDA_VECTOR_GEOMETRY), pinned(0), 
        compute_fat_link_max(false), ghostExchange(QUDA_GHOST_EXCHANGE_PAD),
        staggeredPhaseType(param.staggered_phase_type), 
        staggeredPhaseApplied(param.staggered_phase_applied) 
          {
            if (link_type == QUDA_WILSON_LINKS || link_type == QUDA_ASQTAD_FAT_LINKS) nFace = 1;
            else if (link_type == QUDA_ASQTAD_LONG_LINKS) nFace = 3;
            else errorQuda("Error: invalid link type(%d)\n", link_type);
            for (int d=0; d<nDim; d++) r[d] = 0;
          }
  };
  
  std::ostream& operator<<(std::ostream& output, const GaugeFieldParam& param);

  class GaugeField : public LatticeField {

  protected:
    size_t bytes; // bytes allocated per full field 
    int phase_offset; // offset in bytes to gauge phases - useful to keep track of texture alignment
    int phase_bytes;  // bytes needed to store the phases
    int length;
    int real_length;
    int nColor;
    int nFace;
    QudaFieldGeometry geometry; // whether the field is a scale, vector or tensor

    QudaReconstructType reconstruct;
    QudaGaugeFieldOrder order;
    QudaGaugeFixed fixed;
    QudaLinkType link_type;
    QudaTboundary t_boundary;

    double anisotropy;
    double tadpole;
    double fat_link_max;
    double scale;
  
    
    QudaFieldCreate create; // used to determine the type of field created

    int r[QUDA_MAX_DIM];

    QudaGhostExchange ghostExchange; // the type of ghost exchange to perform
    mutable void *ghost[QUDA_MAX_DIM]; // stores the ghost zone of the gauge field (non-native fields only)

    QudaStaggeredPhase staggeredPhaseType;

    bool staggeredPhaseApplied;

    bool isNative() const;

  public:
    GaugeField(const GaugeFieldParam &param);
    virtual ~GaugeField();

    int Length() const { return length; }
    int Ncolor() const { return nColor; }
    QudaReconstructType Reconstruct() const { return reconstruct; }
    QudaGaugeFieldOrder Order() const { return order; }
    double Anisotropy() const { return anisotropy; }
    double Tadpole() const { return tadpole; }
    double Scale() const { return scale; }  
    QudaTboundary TBoundary() const { return t_boundary; }
    QudaLinkType LinkType() const { return link_type; }
    QudaGaugeFixed GaugeFixed() const { return fixed; }
    QudaGaugeFieldOrder FieldOrder() const { return order; }
    QudaFieldGeometry Geometry() const { return geometry; }
    const int* R() const { return r; }
    QudaGhostExchange GhostExchange() const { return ghostExchange; }
    QudaStaggeredPhase StaggeredPhase() const { return staggeredPhaseType; }

    void applyStaggeredPhase();

    void removeStaggeredPhase();

    const double& LinkMax() const { return fat_link_max; }
    int Nface() const { return nFace; }
  
    void checkField(const GaugeField &);

    size_t Bytes() const { return bytes; }
    size_t PhaseBytes() const { return phase_bytes; }
    size_t PhaseOffset() const { return phase_offset; }

    virtual void* Gauge_p() { errorQuda("Not implemented"); return (void*)0;}
    virtual void* Even_p() { errorQuda("Not implemented"); return (void*)0;}
    virtual void* Odd_p() { errorQuda("Not implemented"); return (void*)0;}

    virtual const void* Gauge_p() const { errorQuda("Not implemented"); return (void*)0;}
    virtual const void* Even_p() const { errorQuda("Not implemented"); return (void*)0;}
    virtual const void* Odd_p() const { errorQuda("Not implemented"); return (void*)0;}

    const void** Ghost() const { 
      if ( isNative() ) errorQuda("No ghost zone pointer for quda-native gauge fields");
      return (const void**)ghost; 
    }
    
  };

  class cudaGaugeField : public GaugeField {

  private:
    void *gauge;
    void *even;
    void *odd;

#ifdef USE_TEXTURE_OBJECTS
    cudaTextureObject_t evenTex;
    cudaTextureObject_t oddTex;
    cudaTextureObject_t evenPhaseTex;
    cudaTextureObject_t oddPhaseTex;
    void createTexObject(cudaTextureObject_t &tex, void *gauge, int isPhase=0);
    void destroyTexObject();
#endif

  public:
    cudaGaugeField(const GaugeFieldParam &);
    virtual ~cudaGaugeField();

    void exchangeGhost(); // exchange the ghost and store store in the padded region

    void exchangeExtendedGhost(const int *R, bool no_comms_fill=false);

    void copy(const GaugeField &);     // generic gauge field copy
    void loadCPUField(const cpuGaugeField &, const QudaFieldLocation &);
    void saveCPUField(cpuGaugeField &, const QudaFieldLocation &) const;

    // (ab)use with care
    void* Gauge_p() { return gauge; }
    void* Even_p() { return even; }
    void* Odd_p() { return odd; }

    const void* Gauge_p() const { return gauge; }
    const void* Even_p() const { return even; }
    const void* Odd_p() const { return odd; }   

#ifdef USE_TEXTURE_OBJECTS
    const cudaTextureObject_t& EvenTex() const { return evenTex; }
    const cudaTextureObject_t& OddTex() const { return oddTex; }
    const cudaTextureObject_t& EvenPhaseTex() const { return evenPhaseTex; }
    const cudaTextureObject_t& OddPhaseTex() const { return oddPhaseTex; }
#endif

    mutable char *backup_h;
    mutable bool backed_up;
    // backs up the cudaGaugeField to CPU memory
    void backup() const;
    // restores the cudaGaugeField to CUDA memory
    void restore();

    void setGauge(void* _gauge); //only allowed when create== QUDA_REFERENCE_FIELD_CREATE
  };

  class cpuGaugeField : public GaugeField {

    friend void cudaGaugeField::copy(const GaugeField &cpu);
    friend void cudaGaugeField::loadCPUField(const cpuGaugeField &cpu, const QudaFieldLocation &);
    friend void cudaGaugeField::saveCPUField(cpuGaugeField &cpu, const QudaFieldLocation &) const;

  private:
    void **gauge; // the actual gauge field
    int pinned;
  
  public:
    cpuGaugeField(const GaugeFieldParam &);
    virtual ~cpuGaugeField();

    void exchangeGhost();

    void exchangeExtendedGhost(const int *R, bool no_comms_fill=false);

    void* Gauge_p() { return gauge; }
    const void* Gauge_p() const { return gauge; }
    void setGauge(void** _gauge); //only allowed when create== QUDA_REFERENCE_FIELD_CREATE
  };

  double norm2(const cudaGaugeField &u);

  void copyGenericGauge(GaugeField &out, const GaugeField &in, QudaFieldLocation location, 
                        void *Out=0, void *In=0, void **ghostOut=0, void **ghostIn=0, int type=0);
  void copyExtendedGauge(GaugeField &out, const GaugeField &in,
                         QudaFieldLocation location, void *Out=0, void *In=0);

  void extractGaugeGhost(const GaugeField &u, void **ghost);

  void extractExtendedGaugeGhost(const GaugeField &u, int dim, const int *R, 
                                 void **ghost, bool extract);

  double maxGauge(const GaugeField &u);

  void applyGaugePhase(GaugeField &u);

} // namespace quda


//FIXME remove this legacy macro
#define gaugeSiteSize 18 // real numbers per gauge field
  
#endif // _GAUGE_QUDA_H