dw_fused_exterior_dslash_core.h

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// *** CUDA DSLASH ***

#define DSLASH_SHARED_FLOATS_PER_THREAD 0


#ifdef MULTI_GPU

#if (CUDA_VERSION >= 4010)
#define VOLATILE
#else
#define VOLATILE volatile
#endif
// input spinor
#ifdef SPINOR_DOUBLE
#define spinorFloat double
#define i00_re I0.x
#define i00_im I0.y
#define i01_re I1.x
#define i01_im I1.y
#define i02_re I2.x
#define i02_im I2.y
#define i10_re I3.x
#define i10_im I3.y
#define i11_re I4.x
#define i11_im I4.y
#define i12_re I5.x
#define i12_im I5.y
#define i20_re I6.x
#define i20_im I6.y
#define i21_re I7.x
#define i21_im I7.y
#define i22_re I8.x
#define i22_im I8.y
#define i30_re I9.x
#define i30_im I9.y
#define i31_re I10.x
#define i31_im I10.y
#define i32_re I11.x
#define i32_im I11.y
#else
#define spinorFloat float
#define i00_re I0.x
#define i00_im I0.y
#define i01_re I0.z
#define i01_im I0.w
#define i02_re I1.x
#define i02_im I1.y
#define i10_re I1.z
#define i10_im I1.w
#define i11_re I2.x
#define i11_im I2.y
#define i12_re I2.z
#define i12_im I2.w
#define i20_re I3.x
#define i20_im I3.y
#define i21_re I3.z
#define i21_im I3.w
#define i22_re I4.x
#define i22_im I4.y
#define i30_re I4.z
#define i30_im I4.w
#define i31_re I5.x
#define i31_im I5.y
#define i32_re I5.z
#define i32_im I5.w
#endif // SPINOR_DOUBLE

// gauge link
#ifdef GAUGE_FLOAT2
#define g00_re G0.x
#define g00_im G0.y
#define g01_re G1.x
#define g01_im G1.y
#define g02_re G2.x
#define g02_im G2.y
#define g10_re G3.x
#define g10_im G3.y
#define g11_re G4.x
#define g11_im G4.y
#define g12_re G5.x
#define g12_im G5.y
#define g20_re G6.x
#define g20_im G6.y
#define g21_re G7.x
#define g21_im G7.y
#define g22_re G8.x
#define g22_im G8.y

#else
#define g00_re G0.x
#define g00_im G0.y
#define g01_re G0.z
#define g01_im G0.w
#define g02_re G1.x
#define g02_im G1.y
#define g10_re G1.z
#define g10_im G1.w
#define g11_re G2.x
#define g11_im G2.y
#define g12_re G2.z
#define g12_im G2.w
#define g20_re G3.x
#define g20_im G3.y
#define g21_re G3.z
#define g21_im G3.w
#define g22_re G4.x
#define g22_im G4.y

#endif // GAUGE_DOUBLE

// conjugated gauge link
#define gT00_re (+g00_re)
#define gT00_im (-g00_im)
#define gT01_re (+g10_re)
#define gT01_im (-g10_im)
#define gT02_re (+g20_re)
#define gT02_im (-g20_im)
#define gT10_re (+g01_re)
#define gT10_im (-g01_im)
#define gT11_re (+g11_re)
#define gT11_im (-g11_im)
#define gT12_re (+g21_re)
#define gT12_im (-g21_im)
#define gT20_re (+g02_re)
#define gT20_im (-g02_im)
#define gT21_re (+g12_re)
#define gT21_im (-g12_im)
#define gT22_re (+g22_re)
#define gT22_im (-g22_im)

// output spinor
VOLATILE spinorFloat o00_re;
VOLATILE spinorFloat o00_im;
VOLATILE spinorFloat o01_re;
VOLATILE spinorFloat o01_im;
VOLATILE spinorFloat o02_re;
VOLATILE spinorFloat o02_im;
VOLATILE spinorFloat o10_re;
VOLATILE spinorFloat o10_im;
VOLATILE spinorFloat o11_re;
VOLATILE spinorFloat o11_im;
VOLATILE spinorFloat o12_re;
VOLATILE spinorFloat o12_im;
VOLATILE spinorFloat o20_re;
VOLATILE spinorFloat o20_im;
VOLATILE spinorFloat o21_re;
VOLATILE spinorFloat o21_im;
VOLATILE spinorFloat o22_re;
VOLATILE spinorFloat o22_im;
VOLATILE spinorFloat o30_re;
VOLATILE spinorFloat o30_im;
VOLATILE spinorFloat o31_re;
VOLATILE spinorFloat o31_im;
VOLATILE spinorFloat o32_re;
VOLATILE spinorFloat o32_im;

#ifdef SPINOR_DOUBLE
#if (__COMPUTE_CAPABILITY__ >= 200)
#define SHARED_STRIDE 16 // to avoid bank conflicts on Fermi
#else
#define SHARED_STRIDE 8 // to avoid bank conflicts on G80 and GT200
#endif
#else
#if (__COMPUTE_CAPABILITY__ >= 200)
#define SHARED_STRIDE 32 // to avoid bank conflicts on Fermi
#else
#define SHARED_STRIDE 16 // to avoid bank conflicts on G80 and GT200
#endif
#endif

#include "read_gauge.h"
#include "io_spinor.h"

#if (DD_PREC==2) // half precision
int sp_norm_idx;
#endif // half precision

int sid = ((blockIdx.y*blockDim.y + threadIdx.y)*gridDim.x + blockIdx.x)*blockDim.x + threadIdx.x;
if (sid >= param.threads*param.dc.Ls) return;

int dim;
int face_idx;
int coord[5];
int X;
int s_parity;



{ // exterior kernel

dim = dimFromFaceIndex<5>(sid, param); // sid is also modified

const int face_volume = ((param.threadDimMapUpper[dim] - param.threadDimMapLower[dim])*param.dc.Ls >> 1);
const int face_num = (sid >= face_volume); // is this thread updating face 0 or 1
face_idx = sid - face_num*face_volume; // index into the respective face

// ghostOffset is scaled to include body (includes stride) and number of FloatN arrays (SPINOR_HOP)
// face_idx not sid since faces are spin projected and share the same volume index (modulo UP/DOWN reading)
//sp_idx = face_idx + param.ghostOffset[dim];

switch(dim) {
case 0:
  coordsFromFaceIndex<5,QUDA_5D_PC,0,1>(X, sid, coord, face_idx, face_num, param);
  break;
case 1:
  coordsFromFaceIndex<5,QUDA_5D_PC,1,1>(X, sid, coord, face_idx, face_num, param);
  break;
case 2:
  coordsFromFaceIndex<5,QUDA_5D_PC,2,1>(X, sid, coord, face_idx, face_num, param);
  break;
case 3:
  coordsFromFaceIndex<5,QUDA_5D_PC,3,1>(X, sid, coord, face_idx, face_num, param);
  break;
}

bool active = false;
for(int dir=0; dir<4; ++dir){
  active = active || isActive(dim,dir,+1,coord,param.commDim,param.dc.X);
}
if(!active) return;


s_parity = ( sid/param.dc.volume_4d_cb ) % 2;

READ_INTERMEDIATE_SPINOR(INTERTEX, param.sp_stride, sid, sid);

 o00_re = i00_re; o00_im = i00_im;
 o01_re = i01_re; o01_im = i01_im;
 o02_re = i02_re; o02_im = i02_im;
 o10_re = i10_re; o10_im = i10_im;
 o11_re = i11_re; o11_im = i11_im;
 o12_re = i12_re; o12_im = i12_im;
 o20_re = i20_re; o20_im = i20_im;
 o21_re = i21_re; o21_im = i21_im;
 o22_re = i22_re; o22_im = i22_im;
 o30_re = i30_re; o30_im = i30_im;
 o31_re = i31_re; o31_im = i31_im;
 o32_re = i32_re; o32_im = i32_im;
}

// declare G## here and use ASSN below instead of READ
#ifdef GAUGE_FLOAT2
#if (DD_PREC==0) //temporal hack
double2 G0;
double2 G1;
double2 G2;
double2 G3;
double2 G4;
double2 G5;
double2 G6;
double2 G7;
double2 G8;
#else
float2 G0;
float2 G1;
float2 G2;
float2 G3;
float2 G4;
float2 G5;
float2 G6;
float2 G7;
float2 G8;
#endif
#else
float4 G0;
float4 G1;
float4 G2;
float4 G3;
float4 G4;
#endif



if (isActive(dim,0,+1,coord,param.commDim,param.dc.X) && coord[0]==(param.dc.X[0]-1) )
{
 // Projector P0-
 //  1  0  0 -i
 //  0  1 -i  0
 //  0  i  1  0
 //  i  0  0  1

 faceIndexFromCoords<5,1>(face_idx,coord,0,param);
 const int sp_idx = face_idx + param.ghostOffset[0][1];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[0][1];
#endif


 const int ga_idx = sid % param.dc.volume_4d_cb;

 // read gauge matrix from device memory
 if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 0, ga_idx, param.gauge_stride); }
 else { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 0, ga_idx, param.gauge_stride); }

 spinorFloat a0_re, a0_im;
 spinorFloat a1_re, a1_im;
 spinorFloat a2_re, a2_im;
 spinorFloat b0_re, b0_im;
 spinorFloat b1_re, b1_im;
 spinorFloat b2_re, b2_im;

 {

  const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[0];

  // read half spinor from device memory
  READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 0);

  a0_re = i00_re; a0_im = i00_im;
  a1_re = i01_re; a1_im = i01_im;
  a2_re = i02_re; a2_im = i02_im;
  b0_re = i10_re; b0_im = i10_im;
  b1_re = i11_re; b1_im = i11_im;
  b2_re = i12_re; b2_im = i12_im;

 }

 // reconstruct gauge matrix
 RECONSTRUCT_GAUGE_MATRIX(0);

 // multiply row 0
 spinorFloat A0_re = 0;
 A0_re += g00_re * a0_re;
 A0_re -= g00_im * a0_im;
 A0_re += g01_re * a1_re;
 A0_re -= g01_im * a1_im;
 A0_re += g02_re * a2_re;
 A0_re -= g02_im * a2_im;
 spinorFloat A0_im = 0;
 A0_im += g00_re * a0_im;
 A0_im += g00_im * a0_re;
 A0_im += g01_re * a1_im;
 A0_im += g01_im * a1_re;
 A0_im += g02_re * a2_im;
 A0_im += g02_im * a2_re;
 spinorFloat B0_re = 0;
 B0_re += g00_re * b0_re;
 B0_re -= g00_im * b0_im;
 B0_re += g01_re * b1_re;
 B0_re -= g01_im * b1_im;
 B0_re += g02_re * b2_re;
 B0_re -= g02_im * b2_im;
 spinorFloat B0_im = 0;
 B0_im += g00_re * b0_im;
 B0_im += g00_im * b0_re;
 B0_im += g01_re * b1_im;
 B0_im += g01_im * b1_re;
 B0_im += g02_re * b2_im;
 B0_im += g02_im * b2_re;

 // multiply row 1
 spinorFloat A1_re = 0;
 A1_re += g10_re * a0_re;
 A1_re -= g10_im * a0_im;
 A1_re += g11_re * a1_re;
 A1_re -= g11_im * a1_im;
 A1_re += g12_re * a2_re;
 A1_re -= g12_im * a2_im;
 spinorFloat A1_im = 0;
 A1_im += g10_re * a0_im;
 A1_im += g10_im * a0_re;
 A1_im += g11_re * a1_im;
 A1_im += g11_im * a1_re;
 A1_im += g12_re * a2_im;
 A1_im += g12_im * a2_re;
 spinorFloat B1_re = 0;
 B1_re += g10_re * b0_re;
 B1_re -= g10_im * b0_im;
 B1_re += g11_re * b1_re;
 B1_re -= g11_im * b1_im;
 B1_re += g12_re * b2_re;
 B1_re -= g12_im * b2_im;
 spinorFloat B1_im = 0;
 B1_im += g10_re * b0_im;
 B1_im += g10_im * b0_re;
 B1_im += g11_re * b1_im;
 B1_im += g11_im * b1_re;
 B1_im += g12_re * b2_im;
 B1_im += g12_im * b2_re;

 // multiply row 2
 spinorFloat A2_re = 0;
 A2_re += g20_re * a0_re;
 A2_re -= g20_im * a0_im;
 A2_re += g21_re * a1_re;
 A2_re -= g21_im * a1_im;
 A2_re += g22_re * a2_re;
 A2_re -= g22_im * a2_im;
 spinorFloat A2_im = 0;
 A2_im += g20_re * a0_im;
 A2_im += g20_im * a0_re;
 A2_im += g21_re * a1_im;
 A2_im += g21_im * a1_re;
 A2_im += g22_re * a2_im;
 A2_im += g22_im * a2_re;
 spinorFloat B2_re = 0;
 B2_re += g20_re * b0_re;
 B2_re -= g20_im * b0_im;
 B2_re += g21_re * b1_re;
 B2_re -= g21_im * b1_im;
 B2_re += g22_re * b2_re;
 B2_re -= g22_im * b2_im;
 spinorFloat B2_im = 0;
 B2_im += g20_re * b0_im;
 B2_im += g20_im * b0_re;
 B2_im += g21_re * b1_im;
 B2_im += g21_im * b1_re;
 B2_im += g22_re * b2_im;
 B2_im += g22_im * b2_re;

 o00_re += A0_re;
 o00_im += A0_im;
 o10_re += B0_re;
 o10_im += B0_im;
 o20_re -= B0_im;
 o20_im += B0_re;
 o30_re -= A0_im;
 o30_im += A0_re;

 o01_re += A1_re;
 o01_im += A1_im;
 o11_re += B1_re;
 o11_im += B1_im;
 o21_re -= B1_im;
 o21_im += B1_re;
 o31_re -= A1_im;
 o31_im += A1_re;

 o02_re += A2_re;
 o02_im += A2_im;
 o12_re += B2_re;
 o12_im += B2_im;
 o22_re -= B2_im;
 o22_im += B2_re;
 o32_re -= A2_im;
 o32_im += A2_re;
}

if (isActive(dim,0,-1,coord,param.commDim,param.dc.X) && coord[0]==0 )
{
 // Projector P0+
 //  1  0  0  i
 //  0  1  i  0
 //  0 -i  1  0
 // -i  0  0  1

 faceIndexFromCoords<5,1>(face_idx,coord,0,param);
 const int sp_idx = face_idx + param.ghostOffset[0][0];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[0][0];
#endif


 const int ga_idx = param.dc.volume_4d_cb+(face_idx % param.dc.ghostFace[0]);

 // read gauge matrix from device memory
 if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 1, ga_idx, param.gauge_stride); }
 else { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 1, ga_idx, param.gauge_stride); }

 spinorFloat a0_re, a0_im;
 spinorFloat a1_re, a1_im;
 spinorFloat a2_re, a2_im;
 spinorFloat b0_re, b0_im;
 spinorFloat b1_re, b1_im;
 spinorFloat b2_re, b2_im;

 {

  const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[0];

  // read half spinor from device memory
  READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 1);

  a0_re = i00_re; a0_im = i00_im;
  a1_re = i01_re; a1_im = i01_im;
  a2_re = i02_re; a2_im = i02_im;
  b0_re = i10_re; b0_im = i10_im;
  b1_re = i11_re; b1_im = i11_im;
  b2_re = i12_re; b2_im = i12_im;

 }

 // reconstruct gauge matrix
 RECONSTRUCT_GAUGE_MATRIX(1);

 // multiply row 0
 spinorFloat A0_re = 0;
 A0_re += gT00_re * a0_re;
 A0_re -= gT00_im * a0_im;
 A0_re += gT01_re * a1_re;
 A0_re -= gT01_im * a1_im;
 A0_re += gT02_re * a2_re;
 A0_re -= gT02_im * a2_im;
 spinorFloat A0_im = 0;
 A0_im += gT00_re * a0_im;
 A0_im += gT00_im * a0_re;
 A0_im += gT01_re * a1_im;
 A0_im += gT01_im * a1_re;
 A0_im += gT02_re * a2_im;
 A0_im += gT02_im * a2_re;
 spinorFloat B0_re = 0;
 B0_re += gT00_re * b0_re;
 B0_re -= gT00_im * b0_im;
 B0_re += gT01_re * b1_re;
 B0_re -= gT01_im * b1_im;
 B0_re += gT02_re * b2_re;
 B0_re -= gT02_im * b2_im;
 spinorFloat B0_im = 0;
 B0_im += gT00_re * b0_im;
 B0_im += gT00_im * b0_re;
 B0_im += gT01_re * b1_im;
 B0_im += gT01_im * b1_re;
 B0_im += gT02_re * b2_im;
 B0_im += gT02_im * b2_re;

 // multiply row 1
 spinorFloat A1_re = 0;
 A1_re += gT10_re * a0_re;
 A1_re -= gT10_im * a0_im;
 A1_re += gT11_re * a1_re;
 A1_re -= gT11_im * a1_im;
 A1_re += gT12_re * a2_re;
 A1_re -= gT12_im * a2_im;
 spinorFloat A1_im = 0;
 A1_im += gT10_re * a0_im;
 A1_im += gT10_im * a0_re;
 A1_im += gT11_re * a1_im;
 A1_im += gT11_im * a1_re;
 A1_im += gT12_re * a2_im;
 A1_im += gT12_im * a2_re;
 spinorFloat B1_re = 0;
 B1_re += gT10_re * b0_re;
 B1_re -= gT10_im * b0_im;
 B1_re += gT11_re * b1_re;
 B1_re -= gT11_im * b1_im;
 B1_re += gT12_re * b2_re;
 B1_re -= gT12_im * b2_im;
 spinorFloat B1_im = 0;
 B1_im += gT10_re * b0_im;
 B1_im += gT10_im * b0_re;
 B1_im += gT11_re * b1_im;
 B1_im += gT11_im * b1_re;
 B1_im += gT12_re * b2_im;
 B1_im += gT12_im * b2_re;

 // multiply row 2
 spinorFloat A2_re = 0;
 A2_re += gT20_re * a0_re;
 A2_re -= gT20_im * a0_im;
 A2_re += gT21_re * a1_re;
 A2_re -= gT21_im * a1_im;
 A2_re += gT22_re * a2_re;
 A2_re -= gT22_im * a2_im;
 spinorFloat A2_im = 0;
 A2_im += gT20_re * a0_im;
 A2_im += gT20_im * a0_re;
 A2_im += gT21_re * a1_im;
 A2_im += gT21_im * a1_re;
 A2_im += gT22_re * a2_im;
 A2_im += gT22_im * a2_re;
 spinorFloat B2_re = 0;
 B2_re += gT20_re * b0_re;
 B2_re -= gT20_im * b0_im;
 B2_re += gT21_re * b1_re;
 B2_re -= gT21_im * b1_im;
 B2_re += gT22_re * b2_re;
 B2_re -= gT22_im * b2_im;
 spinorFloat B2_im = 0;
 B2_im += gT20_re * b0_im;
 B2_im += gT20_im * b0_re;
 B2_im += gT21_re * b1_im;
 B2_im += gT21_im * b1_re;
 B2_im += gT22_re * b2_im;
 B2_im += gT22_im * b2_re;

 o00_re += A0_re;
 o00_im += A0_im;
 o10_re += B0_re;
 o10_im += B0_im;
 o20_re += B0_im;
 o20_im -= B0_re;
 o30_re += A0_im;
 o30_im -= A0_re;

 o01_re += A1_re;
 o01_im += A1_im;
 o11_re += B1_re;
 o11_im += B1_im;
 o21_re += B1_im;
 o21_im -= B1_re;
 o31_re += A1_im;
 o31_im -= A1_re;

 o02_re += A2_re;
 o02_im += A2_im;
 o12_re += B2_re;
 o12_im += B2_im;
 o22_re += B2_im;
 o22_im -= B2_re;
 o32_re += A2_im;
 o32_im -= A2_re;
}

if (isActive(dim,1,+1,coord,param.commDim,param.dc.X) && coord[1]==(param.dc.X[1]-1) )
{
 // Projector P1-
 //  1  0  0 -1
 //  0  1  1  0
 //  0  1  1  0
 // -1  0  0  1

 faceIndexFromCoords<5,1>(face_idx,coord,1,param);
 const int sp_idx = face_idx + param.ghostOffset[1][1];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[1][1];
#endif


 const int ga_idx = sid % param.dc.volume_4d_cb;

 // read gauge matrix from device memory
 if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 2, ga_idx, param.gauge_stride); }
 else { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 2, ga_idx, param.gauge_stride); }

 spinorFloat a0_re, a0_im;
 spinorFloat a1_re, a1_im;
 spinorFloat a2_re, a2_im;
 spinorFloat b0_re, b0_im;
 spinorFloat b1_re, b1_im;
 spinorFloat b2_re, b2_im;

 {

  const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[1];

  // read half spinor from device memory
  READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 2);

  a0_re = i00_re; a0_im = i00_im;
  a1_re = i01_re; a1_im = i01_im;
  a2_re = i02_re; a2_im = i02_im;
  b0_re = i10_re; b0_im = i10_im;
  b1_re = i11_re; b1_im = i11_im;
  b2_re = i12_re; b2_im = i12_im;

 }

 // reconstruct gauge matrix
 RECONSTRUCT_GAUGE_MATRIX(2);

 // multiply row 0
 spinorFloat A0_re = 0;
 A0_re += g00_re * a0_re;
 A0_re -= g00_im * a0_im;
 A0_re += g01_re * a1_re;
 A0_re -= g01_im * a1_im;
 A0_re += g02_re * a2_re;
 A0_re -= g02_im * a2_im;
 spinorFloat A0_im = 0;
 A0_im += g00_re * a0_im;
 A0_im += g00_im * a0_re;
 A0_im += g01_re * a1_im;
 A0_im += g01_im * a1_re;
 A0_im += g02_re * a2_im;
 A0_im += g02_im * a2_re;
 spinorFloat B0_re = 0;
 B0_re += g00_re * b0_re;
 B0_re -= g00_im * b0_im;
 B0_re += g01_re * b1_re;
 B0_re -= g01_im * b1_im;
 B0_re += g02_re * b2_re;
 B0_re -= g02_im * b2_im;
 spinorFloat B0_im = 0;
 B0_im += g00_re * b0_im;
 B0_im += g00_im * b0_re;
 B0_im += g01_re * b1_im;
 B0_im += g01_im * b1_re;
 B0_im += g02_re * b2_im;
 B0_im += g02_im * b2_re;

 // multiply row 1
 spinorFloat A1_re = 0;
 A1_re += g10_re * a0_re;
 A1_re -= g10_im * a0_im;
 A1_re += g11_re * a1_re;
 A1_re -= g11_im * a1_im;
 A1_re += g12_re * a2_re;
 A1_re -= g12_im * a2_im;
 spinorFloat A1_im = 0;
 A1_im += g10_re * a0_im;
 A1_im += g10_im * a0_re;
 A1_im += g11_re * a1_im;
 A1_im += g11_im * a1_re;
 A1_im += g12_re * a2_im;
 A1_im += g12_im * a2_re;
 spinorFloat B1_re = 0;
 B1_re += g10_re * b0_re;
 B1_re -= g10_im * b0_im;
 B1_re += g11_re * b1_re;
 B1_re -= g11_im * b1_im;
 B1_re += g12_re * b2_re;
 B1_re -= g12_im * b2_im;
 spinorFloat B1_im = 0;
 B1_im += g10_re * b0_im;
 B1_im += g10_im * b0_re;
 B1_im += g11_re * b1_im;
 B1_im += g11_im * b1_re;
 B1_im += g12_re * b2_im;
 B1_im += g12_im * b2_re;

 // multiply row 2
 spinorFloat A2_re = 0;
 A2_re += g20_re * a0_re;
 A2_re -= g20_im * a0_im;
 A2_re += g21_re * a1_re;
 A2_re -= g21_im * a1_im;
 A2_re += g22_re * a2_re;
 A2_re -= g22_im * a2_im;
 spinorFloat A2_im = 0;
 A2_im += g20_re * a0_im;
 A2_im += g20_im * a0_re;
 A2_im += g21_re * a1_im;
 A2_im += g21_im * a1_re;
 A2_im += g22_re * a2_im;
 A2_im += g22_im * a2_re;
 spinorFloat B2_re = 0;
 B2_re += g20_re * b0_re;
 B2_re -= g20_im * b0_im;
 B2_re += g21_re * b1_re;
 B2_re -= g21_im * b1_im;
 B2_re += g22_re * b2_re;
 B2_re -= g22_im * b2_im;
 spinorFloat B2_im = 0;
 B2_im += g20_re * b0_im;
 B2_im += g20_im * b0_re;
 B2_im += g21_re * b1_im;
 B2_im += g21_im * b1_re;
 B2_im += g22_re * b2_im;
 B2_im += g22_im * b2_re;

 o00_re += A0_re;
 o00_im += A0_im;
 o10_re += B0_re;
 o10_im += B0_im;
 o20_re += B0_re;
 o20_im += B0_im;
 o30_re -= A0_re;
 o30_im -= A0_im;

 o01_re += A1_re;
 o01_im += A1_im;
 o11_re += B1_re;
 o11_im += B1_im;
 o21_re += B1_re;
 o21_im += B1_im;
 o31_re -= A1_re;
 o31_im -= A1_im;

 o02_re += A2_re;
 o02_im += A2_im;
 o12_re += B2_re;
 o12_im += B2_im;
 o22_re += B2_re;
 o22_im += B2_im;
 o32_re -= A2_re;
 o32_im -= A2_im;
}

if (isActive(dim,1,-1,coord,param.commDim,param.dc.X) && coord[1]==0 )
{
 // Projector P1+
 //  1  0  0  1
 //  0  1 -1  0
 //  0 -1  1  0
 //  1  0  0  1

 faceIndexFromCoords<5,1>(face_idx,coord,1,param);
 const int sp_idx = face_idx + param.ghostOffset[1][0];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[1][0];
#endif


 const int ga_idx = param.dc.volume_4d_cb+(face_idx % param.dc.ghostFace[1]);

 // read gauge matrix from device memory
 if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 3, ga_idx, param.gauge_stride); }
 else { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 3, ga_idx, param.gauge_stride); }

 spinorFloat a0_re, a0_im;
 spinorFloat a1_re, a1_im;
 spinorFloat a2_re, a2_im;
 spinorFloat b0_re, b0_im;
 spinorFloat b1_re, b1_im;
 spinorFloat b2_re, b2_im;

 {

  const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[1];

  // read half spinor from device memory
  READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 3);

  a0_re = i00_re; a0_im = i00_im;
  a1_re = i01_re; a1_im = i01_im;
  a2_re = i02_re; a2_im = i02_im;
  b0_re = i10_re; b0_im = i10_im;
  b1_re = i11_re; b1_im = i11_im;
  b2_re = i12_re; b2_im = i12_im;

 }

 // reconstruct gauge matrix
 RECONSTRUCT_GAUGE_MATRIX(3);

 // multiply row 0
 spinorFloat A0_re = 0;
 A0_re += gT00_re * a0_re;
 A0_re -= gT00_im * a0_im;
 A0_re += gT01_re * a1_re;
 A0_re -= gT01_im * a1_im;
 A0_re += gT02_re * a2_re;
 A0_re -= gT02_im * a2_im;
 spinorFloat A0_im = 0;
 A0_im += gT00_re * a0_im;
 A0_im += gT00_im * a0_re;
 A0_im += gT01_re * a1_im;
 A0_im += gT01_im * a1_re;
 A0_im += gT02_re * a2_im;
 A0_im += gT02_im * a2_re;
 spinorFloat B0_re = 0;
 B0_re += gT00_re * b0_re;
 B0_re -= gT00_im * b0_im;
 B0_re += gT01_re * b1_re;
 B0_re -= gT01_im * b1_im;
 B0_re += gT02_re * b2_re;
 B0_re -= gT02_im * b2_im;
 spinorFloat B0_im = 0;
 B0_im += gT00_re * b0_im;
 B0_im += gT00_im * b0_re;
 B0_im += gT01_re * b1_im;
 B0_im += gT01_im * b1_re;
 B0_im += gT02_re * b2_im;
 B0_im += gT02_im * b2_re;

 // multiply row 1
 spinorFloat A1_re = 0;
 A1_re += gT10_re * a0_re;
 A1_re -= gT10_im * a0_im;
 A1_re += gT11_re * a1_re;
 A1_re -= gT11_im * a1_im;
 A1_re += gT12_re * a2_re;
 A1_re -= gT12_im * a2_im;
 spinorFloat A1_im = 0;
 A1_im += gT10_re * a0_im;
 A1_im += gT10_im * a0_re;
 A1_im += gT11_re * a1_im;
 A1_im += gT11_im * a1_re;
 A1_im += gT12_re * a2_im;
 A1_im += gT12_im * a2_re;
 spinorFloat B1_re = 0;
 B1_re += gT10_re * b0_re;
 B1_re -= gT10_im * b0_im;
 B1_re += gT11_re * b1_re;
 B1_re -= gT11_im * b1_im;
 B1_re += gT12_re * b2_re;
 B1_re -= gT12_im * b2_im;
 spinorFloat B1_im = 0;
 B1_im += gT10_re * b0_im;
 B1_im += gT10_im * b0_re;
 B1_im += gT11_re * b1_im;
 B1_im += gT11_im * b1_re;
 B1_im += gT12_re * b2_im;
 B1_im += gT12_im * b2_re;

 // multiply row 2
 spinorFloat A2_re = 0;
 A2_re += gT20_re * a0_re;
 A2_re -= gT20_im * a0_im;
 A2_re += gT21_re * a1_re;
 A2_re -= gT21_im * a1_im;
 A2_re += gT22_re * a2_re;
 A2_re -= gT22_im * a2_im;
 spinorFloat A2_im = 0;
 A2_im += gT20_re * a0_im;
 A2_im += gT20_im * a0_re;
 A2_im += gT21_re * a1_im;
 A2_im += gT21_im * a1_re;
 A2_im += gT22_re * a2_im;
 A2_im += gT22_im * a2_re;
 spinorFloat B2_re = 0;
 B2_re += gT20_re * b0_re;
 B2_re -= gT20_im * b0_im;
 B2_re += gT21_re * b1_re;
 B2_re -= gT21_im * b1_im;
 B2_re += gT22_re * b2_re;
 B2_re -= gT22_im * b2_im;
 spinorFloat B2_im = 0;
 B2_im += gT20_re * b0_im;
 B2_im += gT20_im * b0_re;
 B2_im += gT21_re * b1_im;
 B2_im += gT21_im * b1_re;
 B2_im += gT22_re * b2_im;
 B2_im += gT22_im * b2_re;

 o00_re += A0_re;
 o00_im += A0_im;
 o10_re += B0_re;
 o10_im += B0_im;
 o20_re -= B0_re;
 o20_im -= B0_im;
 o30_re += A0_re;
 o30_im += A0_im;

 o01_re += A1_re;
 o01_im += A1_im;
 o11_re += B1_re;
 o11_im += B1_im;
 o21_re -= B1_re;
 o21_im -= B1_im;
 o31_re += A1_re;
 o31_im += A1_im;

 o02_re += A2_re;
 o02_im += A2_im;
 o12_re += B2_re;
 o12_im += B2_im;
 o22_re -= B2_re;
 o22_im -= B2_im;
 o32_re += A2_re;
 o32_im += A2_im;
}

if (isActive(dim,2,+1,coord,param.commDim,param.dc.X) && coord[2]==(param.dc.X[2]-1) )
{
 // Projector P2-
 //  1  0 -i  0
 //  0  1  0  i
 //  i  0  1  0
 //  0 -i  0  1

 faceIndexFromCoords<5,1>(face_idx,coord,2,param);
 const int sp_idx = face_idx + param.ghostOffset[2][1];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[2][1];
#endif


 const int ga_idx = sid % param.dc.volume_4d_cb;

 // read gauge matrix from device memory
 if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 4, ga_idx, param.gauge_stride); }
 else { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 4, ga_idx, param.gauge_stride); }

 spinorFloat a0_re, a0_im;
 spinorFloat a1_re, a1_im;
 spinorFloat a2_re, a2_im;
 spinorFloat b0_re, b0_im;
 spinorFloat b1_re, b1_im;
 spinorFloat b2_re, b2_im;

 {

  const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[2];

  // read half spinor from device memory
  READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 4);

  a0_re = i00_re; a0_im = i00_im;
  a1_re = i01_re; a1_im = i01_im;
  a2_re = i02_re; a2_im = i02_im;
  b0_re = i10_re; b0_im = i10_im;
  b1_re = i11_re; b1_im = i11_im;
  b2_re = i12_re; b2_im = i12_im;

 }

 // reconstruct gauge matrix
 RECONSTRUCT_GAUGE_MATRIX(4);

 // multiply row 0
 spinorFloat A0_re = 0;
 A0_re += g00_re * a0_re;
 A0_re -= g00_im * a0_im;
 A0_re += g01_re * a1_re;
 A0_re -= g01_im * a1_im;
 A0_re += g02_re * a2_re;
 A0_re -= g02_im * a2_im;
 spinorFloat A0_im = 0;
 A0_im += g00_re * a0_im;
 A0_im += g00_im * a0_re;
 A0_im += g01_re * a1_im;
 A0_im += g01_im * a1_re;
 A0_im += g02_re * a2_im;
 A0_im += g02_im * a2_re;
 spinorFloat B0_re = 0;
 B0_re += g00_re * b0_re;
 B0_re -= g00_im * b0_im;
 B0_re += g01_re * b1_re;
 B0_re -= g01_im * b1_im;
 B0_re += g02_re * b2_re;
 B0_re -= g02_im * b2_im;
 spinorFloat B0_im = 0;
 B0_im += g00_re * b0_im;
 B0_im += g00_im * b0_re;
 B0_im += g01_re * b1_im;
 B0_im += g01_im * b1_re;
 B0_im += g02_re * b2_im;
 B0_im += g02_im * b2_re;

 // multiply row 1
 spinorFloat A1_re = 0;
 A1_re += g10_re * a0_re;
 A1_re -= g10_im * a0_im;
 A1_re += g11_re * a1_re;
 A1_re -= g11_im * a1_im;
 A1_re += g12_re * a2_re;
 A1_re -= g12_im * a2_im;
 spinorFloat A1_im = 0;
 A1_im += g10_re * a0_im;
 A1_im += g10_im * a0_re;
 A1_im += g11_re * a1_im;
 A1_im += g11_im * a1_re;
 A1_im += g12_re * a2_im;
 A1_im += g12_im * a2_re;
 spinorFloat B1_re = 0;
 B1_re += g10_re * b0_re;
 B1_re -= g10_im * b0_im;
 B1_re += g11_re * b1_re;
 B1_re -= g11_im * b1_im;
 B1_re += g12_re * b2_re;
 B1_re -= g12_im * b2_im;
 spinorFloat B1_im = 0;
 B1_im += g10_re * b0_im;
 B1_im += g10_im * b0_re;
 B1_im += g11_re * b1_im;
 B1_im += g11_im * b1_re;
 B1_im += g12_re * b2_im;
 B1_im += g12_im * b2_re;

 // multiply row 2
 spinorFloat A2_re = 0;
 A2_re += g20_re * a0_re;
 A2_re -= g20_im * a0_im;
 A2_re += g21_re * a1_re;
 A2_re -= g21_im * a1_im;
 A2_re += g22_re * a2_re;
 A2_re -= g22_im * a2_im;
 spinorFloat A2_im = 0;
 A2_im += g20_re * a0_im;
 A2_im += g20_im * a0_re;
 A2_im += g21_re * a1_im;
 A2_im += g21_im * a1_re;
 A2_im += g22_re * a2_im;
 A2_im += g22_im * a2_re;
 spinorFloat B2_re = 0;
 B2_re += g20_re * b0_re;
 B2_re -= g20_im * b0_im;
 B2_re += g21_re * b1_re;
 B2_re -= g21_im * b1_im;
 B2_re += g22_re * b2_re;
 B2_re -= g22_im * b2_im;
 spinorFloat B2_im = 0;
 B2_im += g20_re * b0_im;
 B2_im += g20_im * b0_re;
 B2_im += g21_re * b1_im;
 B2_im += g21_im * b1_re;
 B2_im += g22_re * b2_im;
 B2_im += g22_im * b2_re;

 o00_re += A0_re;
 o00_im += A0_im;
 o10_re += B0_re;
 o10_im += B0_im;
 o20_re -= A0_im;
 o20_im += A0_re;
 o30_re += B0_im;
 o30_im -= B0_re;

 o01_re += A1_re;
 o01_im += A1_im;
 o11_re += B1_re;
 o11_im += B1_im;
 o21_re -= A1_im;
 o21_im += A1_re;
 o31_re += B1_im;
 o31_im -= B1_re;

 o02_re += A2_re;
 o02_im += A2_im;
 o12_re += B2_re;
 o12_im += B2_im;
 o22_re -= A2_im;
 o22_im += A2_re;
 o32_re += B2_im;
 o32_im -= B2_re;
}

if (isActive(dim,2,-1,coord,param.commDim,param.dc.X) && coord[2]==0 )
{
 // Projector P2+
 //  1  0  i  0
 //  0  1  0 -i
 // -i  0  1  0
 //  0  i  0  1

 faceIndexFromCoords<5,1>(face_idx,coord,2,param);
 const int sp_idx = face_idx + param.ghostOffset[2][0];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[2][0];
#endif


 const int ga_idx = param.dc.volume_4d_cb+(face_idx % param.dc.ghostFace[2]);

 // read gauge matrix from device memory
 if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 5, ga_idx, param.gauge_stride); }
 else { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 5, ga_idx, param.gauge_stride); }

 spinorFloat a0_re, a0_im;
 spinorFloat a1_re, a1_im;
 spinorFloat a2_re, a2_im;
 spinorFloat b0_re, b0_im;
 spinorFloat b1_re, b1_im;
 spinorFloat b2_re, b2_im;

 {

  const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[2];

  // read half spinor from device memory
  READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 5);

  a0_re = i00_re; a0_im = i00_im;
  a1_re = i01_re; a1_im = i01_im;
  a2_re = i02_re; a2_im = i02_im;
  b0_re = i10_re; b0_im = i10_im;
  b1_re = i11_re; b1_im = i11_im;
  b2_re = i12_re; b2_im = i12_im;

 }

 // reconstruct gauge matrix
 RECONSTRUCT_GAUGE_MATRIX(5);

 // multiply row 0
 spinorFloat A0_re = 0;
 A0_re += gT00_re * a0_re;
 A0_re -= gT00_im * a0_im;
 A0_re += gT01_re * a1_re;
 A0_re -= gT01_im * a1_im;
 A0_re += gT02_re * a2_re;
 A0_re -= gT02_im * a2_im;
 spinorFloat A0_im = 0;
 A0_im += gT00_re * a0_im;
 A0_im += gT00_im * a0_re;
 A0_im += gT01_re * a1_im;
 A0_im += gT01_im * a1_re;
 A0_im += gT02_re * a2_im;
 A0_im += gT02_im * a2_re;
 spinorFloat B0_re = 0;
 B0_re += gT00_re * b0_re;
 B0_re -= gT00_im * b0_im;
 B0_re += gT01_re * b1_re;
 B0_re -= gT01_im * b1_im;
 B0_re += gT02_re * b2_re;
 B0_re -= gT02_im * b2_im;
 spinorFloat B0_im = 0;
 B0_im += gT00_re * b0_im;
 B0_im += gT00_im * b0_re;
 B0_im += gT01_re * b1_im;
 B0_im += gT01_im * b1_re;
 B0_im += gT02_re * b2_im;
 B0_im += gT02_im * b2_re;

 // multiply row 1
 spinorFloat A1_re = 0;
 A1_re += gT10_re * a0_re;
 A1_re -= gT10_im * a0_im;
 A1_re += gT11_re * a1_re;
 A1_re -= gT11_im * a1_im;
 A1_re += gT12_re * a2_re;
 A1_re -= gT12_im * a2_im;
 spinorFloat A1_im = 0;
 A1_im += gT10_re * a0_im;
 A1_im += gT10_im * a0_re;
 A1_im += gT11_re * a1_im;
 A1_im += gT11_im * a1_re;
 A1_im += gT12_re * a2_im;
 A1_im += gT12_im * a2_re;
 spinorFloat B1_re = 0;
 B1_re += gT10_re * b0_re;
 B1_re -= gT10_im * b0_im;
 B1_re += gT11_re * b1_re;
 B1_re -= gT11_im * b1_im;
 B1_re += gT12_re * b2_re;
 B1_re -= gT12_im * b2_im;
 spinorFloat B1_im = 0;
 B1_im += gT10_re * b0_im;
 B1_im += gT10_im * b0_re;
 B1_im += gT11_re * b1_im;
 B1_im += gT11_im * b1_re;
 B1_im += gT12_re * b2_im;
 B1_im += gT12_im * b2_re;

 // multiply row 2
 spinorFloat A2_re = 0;
 A2_re += gT20_re * a0_re;
 A2_re -= gT20_im * a0_im;
 A2_re += gT21_re * a1_re;
 A2_re -= gT21_im * a1_im;
 A2_re += gT22_re * a2_re;
 A2_re -= gT22_im * a2_im;
 spinorFloat A2_im = 0;
 A2_im += gT20_re * a0_im;
 A2_im += gT20_im * a0_re;
 A2_im += gT21_re * a1_im;
 A2_im += gT21_im * a1_re;
 A2_im += gT22_re * a2_im;
 A2_im += gT22_im * a2_re;
 spinorFloat B2_re = 0;
 B2_re += gT20_re * b0_re;
 B2_re -= gT20_im * b0_im;
 B2_re += gT21_re * b1_re;
 B2_re -= gT21_im * b1_im;
 B2_re += gT22_re * b2_re;
 B2_re -= gT22_im * b2_im;
 spinorFloat B2_im = 0;
 B2_im += gT20_re * b0_im;
 B2_im += gT20_im * b0_re;
 B2_im += gT21_re * b1_im;
 B2_im += gT21_im * b1_re;
 B2_im += gT22_re * b2_im;
 B2_im += gT22_im * b2_re;

 o00_re += A0_re;
 o00_im += A0_im;
 o10_re += B0_re;
 o10_im += B0_im;
 o20_re += A0_im;
 o20_im -= A0_re;
 o30_re -= B0_im;
 o30_im += B0_re;

 o01_re += A1_re;
 o01_im += A1_im;
 o11_re += B1_re;
 o11_im += B1_im;
 o21_re += A1_im;
 o21_im -= A1_re;
 o31_re -= B1_im;
 o31_im += B1_re;

 o02_re += A2_re;
 o02_im += A2_im;
 o12_re += B2_re;
 o12_im += B2_im;
 o22_re += A2_im;
 o22_im -= A2_re;
 o32_re -= B2_im;
 o32_im += B2_re;
}

if (isActive(dim,3,+1,coord,param.commDim,param.dc.X) && coord[3]==(param.dc.X[3]-1) )
{
 // Projector P3-
 //  0  0  0  0
 //  0  0  0  0
 //  0  0  2  0
 //  0  0  0  2

 faceIndexFromCoords<5,1>(face_idx,coord,3,param);
 const int sp_idx = face_idx + param.ghostOffset[3][1];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[3][1];
#endif


 const int ga_idx = sid % param.dc.volume_4d_cb;

 if (param.gauge_fixed && ga_idx < param.dc.X4X3X2X1hmX3X2X1h)
 {
  spinorFloat a0_re, a0_im;
  spinorFloat a1_re, a1_im;
  spinorFloat a2_re, a2_im;
  spinorFloat b0_re, b0_im;
  spinorFloat b1_re, b1_im;
  spinorFloat b2_re, b2_im;

  {

   const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[3];
   const int t_proj_scale = TPROJSCALE;

   // read half spinor from device memory
   READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 6);

   a0_re = t_proj_scale*i00_re; a0_im = t_proj_scale*i00_im;
   a1_re = t_proj_scale*i01_re; a1_im = t_proj_scale*i01_im;
   a2_re = t_proj_scale*i02_re; a2_im = t_proj_scale*i02_im;
   b0_re = t_proj_scale*i10_re; b0_im = t_proj_scale*i10_im;
   b1_re = t_proj_scale*i11_re; b1_im = t_proj_scale*i11_im;
   b2_re = t_proj_scale*i12_re; b2_im = t_proj_scale*i12_im;

  }

  // identity gauge matrix
  spinorFloat A0_re = a0_re; spinorFloat A0_im = a0_im;
  spinorFloat B0_re = b0_re; spinorFloat B0_im = b0_im;
  spinorFloat A1_re = a1_re; spinorFloat A1_im = a1_im;
  spinorFloat B1_re = b1_re; spinorFloat B1_im = b1_im;
  spinorFloat A2_re = a2_re; spinorFloat A2_im = a2_im;
  spinorFloat B2_re = b2_re; spinorFloat B2_im = b2_im;

  o20_re += A0_re;
  o20_im += A0_im;
  o30_re += B0_re;
  o30_im += B0_im;

  o21_re += A1_re;
  o21_im += A1_im;
  o31_re += B1_re;
  o31_im += B1_im;

  o22_re += A2_re;
  o22_im += A2_im;
  o32_re += B2_re;
  o32_im += B2_im;
 } else {
  // read gauge matrix from device memory
  if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 6, ga_idx, param.gauge_stride); }
  else { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 6, ga_idx, param.gauge_stride); }

  spinorFloat a0_re, a0_im;
  spinorFloat a1_re, a1_im;
  spinorFloat a2_re, a2_im;
  spinorFloat b0_re, b0_im;
  spinorFloat b1_re, b1_im;
  spinorFloat b2_re, b2_im;

  {

   const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[3];
   const int t_proj_scale = TPROJSCALE;

   // read half spinor from device memory
   READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 6);

   a0_re = t_proj_scale*i00_re; a0_im = t_proj_scale*i00_im;
   a1_re = t_proj_scale*i01_re; a1_im = t_proj_scale*i01_im;
   a2_re = t_proj_scale*i02_re; a2_im = t_proj_scale*i02_im;
   b0_re = t_proj_scale*i10_re; b0_im = t_proj_scale*i10_im;
   b1_re = t_proj_scale*i11_re; b1_im = t_proj_scale*i11_im;
   b2_re = t_proj_scale*i12_re; b2_im = t_proj_scale*i12_im;

  }

  // reconstruct gauge matrix
  RECONSTRUCT_GAUGE_MATRIX(6);

  // multiply row 0
  spinorFloat A0_re = 0;
  A0_re += g00_re * a0_re;
  A0_re -= g00_im * a0_im;
  A0_re += g01_re * a1_re;
  A0_re -= g01_im * a1_im;
  A0_re += g02_re * a2_re;
  A0_re -= g02_im * a2_im;
  spinorFloat A0_im = 0;
  A0_im += g00_re * a0_im;
  A0_im += g00_im * a0_re;
  A0_im += g01_re * a1_im;
  A0_im += g01_im * a1_re;
  A0_im += g02_re * a2_im;
  A0_im += g02_im * a2_re;
  spinorFloat B0_re = 0;
  B0_re += g00_re * b0_re;
  B0_re -= g00_im * b0_im;
  B0_re += g01_re * b1_re;
  B0_re -= g01_im * b1_im;
  B0_re += g02_re * b2_re;
  B0_re -= g02_im * b2_im;
  spinorFloat B0_im = 0;
  B0_im += g00_re * b0_im;
  B0_im += g00_im * b0_re;
  B0_im += g01_re * b1_im;
  B0_im += g01_im * b1_re;
  B0_im += g02_re * b2_im;
  B0_im += g02_im * b2_re;

  // multiply row 1
  spinorFloat A1_re = 0;
  A1_re += g10_re * a0_re;
  A1_re -= g10_im * a0_im;
  A1_re += g11_re * a1_re;
  A1_re -= g11_im * a1_im;
  A1_re += g12_re * a2_re;
  A1_re -= g12_im * a2_im;
  spinorFloat A1_im = 0;
  A1_im += g10_re * a0_im;
  A1_im += g10_im * a0_re;
  A1_im += g11_re * a1_im;
  A1_im += g11_im * a1_re;
  A1_im += g12_re * a2_im;
  A1_im += g12_im * a2_re;
  spinorFloat B1_re = 0;
  B1_re += g10_re * b0_re;
  B1_re -= g10_im * b0_im;
  B1_re += g11_re * b1_re;
  B1_re -= g11_im * b1_im;
  B1_re += g12_re * b2_re;
  B1_re -= g12_im * b2_im;
  spinorFloat B1_im = 0;
  B1_im += g10_re * b0_im;
  B1_im += g10_im * b0_re;
  B1_im += g11_re * b1_im;
  B1_im += g11_im * b1_re;
  B1_im += g12_re * b2_im;
  B1_im += g12_im * b2_re;

  // multiply row 2
  spinorFloat A2_re = 0;
  A2_re += g20_re * a0_re;
  A2_re -= g20_im * a0_im;
  A2_re += g21_re * a1_re;
  A2_re -= g21_im * a1_im;
  A2_re += g22_re * a2_re;
  A2_re -= g22_im * a2_im;
  spinorFloat A2_im = 0;
  A2_im += g20_re * a0_im;
  A2_im += g20_im * a0_re;
  A2_im += g21_re * a1_im;
  A2_im += g21_im * a1_re;
  A2_im += g22_re * a2_im;
  A2_im += g22_im * a2_re;
  spinorFloat B2_re = 0;
  B2_re += g20_re * b0_re;
  B2_re -= g20_im * b0_im;
  B2_re += g21_re * b1_re;
  B2_re -= g21_im * b1_im;
  B2_re += g22_re * b2_re;
  B2_re -= g22_im * b2_im;
  spinorFloat B2_im = 0;
  B2_im += g20_re * b0_im;
  B2_im += g20_im * b0_re;
  B2_im += g21_re * b1_im;
  B2_im += g21_im * b1_re;
  B2_im += g22_re * b2_im;
  B2_im += g22_im * b2_re;

  o20_re += A0_re;
  o20_im += A0_im;
  o30_re += B0_re;
  o30_im += B0_im;

  o21_re += A1_re;
  o21_im += A1_im;
  o31_re += B1_re;
  o31_im += B1_im;

  o22_re += A2_re;
  o22_im += A2_im;
  o32_re += B2_re;
  o32_im += B2_im;
 }
}

if (isActive(dim,3,-1,coord,param.commDim,param.dc.X) && coord[3]==0 )
{
 // Projector P3+
 //  2  0  0  0
 //  0  2  0  0
 //  0  0  0  0
 //  0  0  0  0

 faceIndexFromCoords<5,1>(face_idx,coord,3,param);
 const int sp_idx = face_idx + param.ghostOffset[3][0];
#if (DD_PREC==2) // half precision
   sp_norm_idx = face_idx + param.ghostNormOffset[3][0];
#endif


 const int ga_idx = param.dc.volume_4d_cb+(face_idx % param.dc.ghostFace[3]);

 if (param.gauge_fixed && ga_idx < param.dc.X4X3X2X1hmX3X2X1h)
 {
  spinorFloat a0_re, a0_im;
  spinorFloat a1_re, a1_im;
  spinorFloat a2_re, a2_im;
  spinorFloat b0_re, b0_im;
  spinorFloat b1_re, b1_im;
  spinorFloat b2_re, b2_im;

  {

   const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[3];
   const int t_proj_scale = TPROJSCALE;

   // read half spinor from device memory
   READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 7);

   a0_re = t_proj_scale*i00_re; a0_im = t_proj_scale*i00_im;
   a1_re = t_proj_scale*i01_re; a1_im = t_proj_scale*i01_im;
   a2_re = t_proj_scale*i02_re; a2_im = t_proj_scale*i02_im;
   b0_re = t_proj_scale*i10_re; b0_im = t_proj_scale*i10_im;
   b1_re = t_proj_scale*i11_re; b1_im = t_proj_scale*i11_im;
   b2_re = t_proj_scale*i12_re; b2_im = t_proj_scale*i12_im;

  }

  // identity gauge matrix
  spinorFloat A0_re = a0_re; spinorFloat A0_im = a0_im;
  spinorFloat B0_re = b0_re; spinorFloat B0_im = b0_im;
  spinorFloat A1_re = a1_re; spinorFloat A1_im = a1_im;
  spinorFloat B1_re = b1_re; spinorFloat B1_im = b1_im;
  spinorFloat A2_re = a2_re; spinorFloat A2_im = a2_im;
  spinorFloat B2_re = b2_re; spinorFloat B2_im = b2_im;

  o00_re += A0_re;
  o00_im += A0_im;
  o10_re += B0_re;
  o10_im += B0_im;

  o01_re += A1_re;
  o01_im += A1_im;
  o11_re += B1_re;
  o11_im += B1_im;

  o02_re += A2_re;
  o02_im += A2_im;
  o12_re += B2_re;
  o12_im += B2_im;
 } else {
  // read gauge matrix from device memory
  if ( ! s_parity ) { ASSN_GAUGE_MATRIX(G, GAUGE1TEX, 7, ga_idx, param.gauge_stride); }
  else { ASSN_GAUGE_MATRIX(G, GAUGE0TEX, 7, ga_idx, param.gauge_stride); }

  spinorFloat a0_re, a0_im;
  spinorFloat a1_re, a1_im;
  spinorFloat a2_re, a2_im;
  spinorFloat b0_re, b0_im;
  spinorFloat b1_re, b1_im;
  spinorFloat b2_re, b2_im;

  {

   const int sp_stride_pad = param.dc.Ls*param.dc.ghostFace[3];
   const int t_proj_scale = TPROJSCALE;

   // read half spinor from device memory
   READ_SPINOR_GHOST(GHOSTSPINORTEX, sp_stride_pad, sp_idx, sp_norm_idx, 7);

   a0_re = t_proj_scale*i00_re; a0_im = t_proj_scale*i00_im;
   a1_re = t_proj_scale*i01_re; a1_im = t_proj_scale*i01_im;
   a2_re = t_proj_scale*i02_re; a2_im = t_proj_scale*i02_im;
   b0_re = t_proj_scale*i10_re; b0_im = t_proj_scale*i10_im;
   b1_re = t_proj_scale*i11_re; b1_im = t_proj_scale*i11_im;
   b2_re = t_proj_scale*i12_re; b2_im = t_proj_scale*i12_im;

  }

  // reconstruct gauge matrix
  RECONSTRUCT_GAUGE_MATRIX(7);

  // multiply row 0
  spinorFloat A0_re = 0;
  A0_re += gT00_re * a0_re;
  A0_re -= gT00_im * a0_im;
  A0_re += gT01_re * a1_re;
  A0_re -= gT01_im * a1_im;
  A0_re += gT02_re * a2_re;
  A0_re -= gT02_im * a2_im;
  spinorFloat A0_im = 0;
  A0_im += gT00_re * a0_im;
  A0_im += gT00_im * a0_re;
  A0_im += gT01_re * a1_im;
  A0_im += gT01_im * a1_re;
  A0_im += gT02_re * a2_im;
  A0_im += gT02_im * a2_re;
  spinorFloat B0_re = 0;
  B0_re += gT00_re * b0_re;
  B0_re -= gT00_im * b0_im;
  B0_re += gT01_re * b1_re;
  B0_re -= gT01_im * b1_im;
  B0_re += gT02_re * b2_re;
  B0_re -= gT02_im * b2_im;
  spinorFloat B0_im = 0;
  B0_im += gT00_re * b0_im;
  B0_im += gT00_im * b0_re;
  B0_im += gT01_re * b1_im;
  B0_im += gT01_im * b1_re;
  B0_im += gT02_re * b2_im;
  B0_im += gT02_im * b2_re;

  // multiply row 1
  spinorFloat A1_re = 0;
  A1_re += gT10_re * a0_re;
  A1_re -= gT10_im * a0_im;
  A1_re += gT11_re * a1_re;
  A1_re -= gT11_im * a1_im;
  A1_re += gT12_re * a2_re;
  A1_re -= gT12_im * a2_im;
  spinorFloat A1_im = 0;
  A1_im += gT10_re * a0_im;
  A1_im += gT10_im * a0_re;
  A1_im += gT11_re * a1_im;
  A1_im += gT11_im * a1_re;
  A1_im += gT12_re * a2_im;
  A1_im += gT12_im * a2_re;
  spinorFloat B1_re = 0;
  B1_re += gT10_re * b0_re;
  B1_re -= gT10_im * b0_im;
  B1_re += gT11_re * b1_re;
  B1_re -= gT11_im * b1_im;
  B1_re += gT12_re * b2_re;
  B1_re -= gT12_im * b2_im;
  spinorFloat B1_im = 0;
  B1_im += gT10_re * b0_im;
  B1_im += gT10_im * b0_re;
  B1_im += gT11_re * b1_im;
  B1_im += gT11_im * b1_re;
  B1_im += gT12_re * b2_im;
  B1_im += gT12_im * b2_re;

  // multiply row 2
  spinorFloat A2_re = 0;
  A2_re += gT20_re * a0_re;
  A2_re -= gT20_im * a0_im;
  A2_re += gT21_re * a1_re;
  A2_re -= gT21_im * a1_im;
  A2_re += gT22_re * a2_re;
  A2_re -= gT22_im * a2_im;
  spinorFloat A2_im = 0;
  A2_im += gT20_re * a0_im;
  A2_im += gT20_im * a0_re;
  A2_im += gT21_re * a1_im;
  A2_im += gT21_im * a1_re;
  A2_im += gT22_re * a2_im;
  A2_im += gT22_im * a2_re;
  spinorFloat B2_re = 0;
  B2_re += gT20_re * b0_re;
  B2_re -= gT20_im * b0_im;
  B2_re += gT21_re * b1_re;
  B2_re -= gT21_im * b1_im;
  B2_re += gT22_re * b2_re;
  B2_re -= gT22_im * b2_im;
  spinorFloat B2_im = 0;
  B2_im += gT20_re * b0_im;
  B2_im += gT20_im * b0_re;
  B2_im += gT21_re * b1_im;
  B2_im += gT21_im * b1_re;
  B2_im += gT22_re * b2_im;
  B2_im += gT22_im * b2_re;

  o00_re += A0_re;
  o00_im += A0_im;
  o10_re += B0_re;
  o10_im += B0_im;

  o01_re += A1_re;
  o01_im += A1_im;
  o11_re += B1_re;
  o11_im += B1_im;

  o02_re += A2_re;
  o02_im += A2_im;
  o12_re += B2_re;
  o12_im += B2_im;
 }
}

{

#ifdef DSLASH_XPAY
#ifdef SPINOR_DOUBLE
 spinorFloat a = param.a;
#else
 spinorFloat a = param.a_f;
#endif
#ifdef SPINOR_DOUBLE
  o00_re = a*o00_re;
  o00_im = a*o00_im;
  o01_re = a*o01_re;
  o01_im = a*o01_im;
  o02_re = a*o02_re;
  o02_im = a*o02_im;
  o10_re = a*o10_re;
  o10_im = a*o10_im;
  o11_re = a*o11_re;
  o11_im = a*o11_im;
  o12_re = a*o12_re;
  o12_im = a*o12_im;
  o20_re = a*o20_re;
  o20_im = a*o20_im;
  o21_re = a*o21_re;
  o21_im = a*o21_im;
  o22_re = a*o22_re;
  o22_im = a*o22_im;
  o30_re = a*o30_re;
  o30_im = a*o30_im;
  o31_re = a*o31_re;
  o31_im = a*o31_im;
  o32_re = a*o32_re;
  o32_im = a*o32_im;
#else
  o00_re = a*o00_re;
  o00_im = a*o00_im;
  o01_re = a*o01_re;
  o01_im = a*o01_im;
  o02_re = a*o02_re;
  o02_im = a*o02_im;
  o10_re = a*o10_re;
  o10_im = a*o10_im;
  o11_re = a*o11_re;
  o11_im = a*o11_im;
  o12_re = a*o12_re;
  o12_im = a*o12_im;
  o20_re = a*o20_re;
  o20_im = a*o20_im;
  o21_re = a*o21_re;
  o21_im = a*o21_im;
  o22_re = a*o22_re;
  o22_im = a*o22_im;
  o30_re = a*o30_re;
  o30_im = a*o30_im;
  o31_re = a*o31_re;
  o31_im = a*o31_im;
  o32_re = a*o32_re;
  o32_im = a*o32_im;
#endif // SPINOR_DOUBLE

#endif // DSLASH_XPAY
}

// write spinor field back to device memory
WRITE_SPINOR(param.sp_stride);

// undefine to prevent warning when precision is changed
#undef spinorFloat
#undef SHARED_STRIDE

#undef g00_re
#undef g00_im
#undef g01_re
#undef g01_im
#undef g02_re
#undef g02_im
#undef g10_re
#undef g10_im
#undef g11_re
#undef g11_im
#undef g12_re
#undef g12_im
#undef g20_re
#undef g20_im
#undef g21_re
#undef g21_im
#undef g22_re
#undef g22_im

#undef i00_re
#undef i00_im
#undef i01_re
#undef i01_im
#undef i02_re
#undef i02_im
#undef i10_re
#undef i10_im
#undef i11_re
#undef i11_im
#undef i12_re
#undef i12_im
#undef i20_re
#undef i20_im
#undef i21_re
#undef i21_im
#undef i22_re
#undef i22_im
#undef i30_re
#undef i30_im
#undef i31_re
#undef i31_im
#undef i32_re
#undef i32_im



#undef VOLATILE

#endif // MULTI_GPU