opgrad_kernel.h

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#ifndef __MATH_OPGRAD_KERNEL_H__
#define __MATH_OPGRAD_KERNEL_H__
 
/*
 Copyright (c) 2021-2023, The Neko Authors
 All rights reserved.
 
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 are met:
 
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     notice, this list of conditions and the following disclaimer.
 
   * Redistributions in binary form must reproduce the above
     copyright notice, this list of conditions and the following
     disclaimer in the documentation and/or other materials provided
     with the distribution.
 
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     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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 POSSIBILITY OF SUCH DAMAGE.
*/
 
#include "elem_block.h"
 
template< typename T, const int LX, const int CHUNKS >
__global__ void opgrad_kernel_1d(T * __restrict__ ux,
                                 T * __restrict__ uy,
                                 T * __restrict__ uz,
                                 const T * __restrict__ u,
                                 const T * __restrict__ dx,
                                 const T * __restrict__ dy,
                                 const T * __restrict__ dz,
                                 const T * __restrict__ drdx,
                                 const T * __restrict__ dsdx,
                                 const T * __restrict__ dtdx,
                                 const T * __restrict__ drdy,
                                 const T * __restrict__ dsdy,
                                 const T * __restrict__ dtdy,
                                 const T * __restrict__ drdz,
                                 const T * __restrict__ dsdz,
                                 const T * __restrict__ dtdz,
                                 const T * __restrict__ w3) {
 
  __shared__ T shu[LX * LX * LX];
 
  __shared__ T shdx[LX * LX];
  __shared__ T shdy[LX * LX];
  __shared__ T shdz[LX * LX];
 
 
  int i,j,k;
 
  const int e = blockIdx.x;
  const int iii = threadIdx.x;
  const int nchunks = (LX * LX * LX - 1) / CHUNKS + 1;
 
  if (iii < (LX * LX)) {
    shdx[iii] = dx[iii];
    shdy[iii] = dy[iii];
    shdz[iii] = dz[iii];
  }
 
  j = iii;
  while(j < (LX * LX * LX)) {
    shu[j] = u[j + e * LX * LX * LX];
    j = j + CHUNKS;
  }
 
  __syncthreads();
 
  for (int n = 0; n < nchunks; n++) {
    const int ijk = iii + n * CHUNKS;
    const int jk = ijk / LX;
    i = ijk - jk * LX;
    k = jk / LX;
    j = jk - k * LX;
    if ( i < LX && j < LX && k < LX ) {
      T rtmp = 0.0;
      T stmp = 0.0;
      T ttmp = 0.0;
      for (int l = 0; l < LX; l++) {
    rtmp += shdx[i + l * LX] * shu[l + j * LX + k * LX * LX];
    stmp += shdy[j + l * LX] * shu[i + l * LX + k * LX * LX];
    ttmp += shdz[k + l * LX] * shu[i + j * LX + l * LX * LX];
      }
 
      ux[ijk + e * LX * LX * LX] = w3[ijk]
    * (drdx[ijk + e * LX * LX * LX] * rtmp
       + dsdx[ijk + e * LX * LX * LX] * stmp
       + dtdx[ijk + e * LX * LX * LX] * ttmp);
 
      uy[ijk + e * LX * LX * LX] = w3[ijk]
    * (drdy[ijk + e * LX * LX * LX] * rtmp
       + dsdy[ijk + e * LX * LX * LX] * stmp
       + dtdy[ijk + e * LX * LX * LX] * ttmp);
 
      uz[ijk + e * LX * LX * LX] = w3[ijk]
    * (drdz[ijk + e * LX * LX * LX] * rtmp
       + dsdz[ijk + e * LX * LX * LX] * stmp
       + dtdz[ijk + e * LX * LX * LX] * ttmp);
 
    }
  }
 
}
 
template< typename T, const int LX, const int EB >
__global__ void NEKO_EB_BOUNDS(LX*LX*EB)
opgrad_kernel_kstep(T * __restrict__ ux,
                    T * __restrict__ uy,
                    T * __restrict__ uz,
                    const T * __restrict__ u,
                    const T * __restrict__ dx,
                    const T * __restrict__ dy,
                    const T * __restrict__ dz,
                    const T * __restrict__ drdx,
                    const T * __restrict__ dsdx,
                    const T * __restrict__ dtdx,
                    const T * __restrict__ drdy,
                    const T * __restrict__ dsdy,
                    const T * __restrict__ dtdy,
                    const T * __restrict__ drdz,
                    const T * __restrict__ dsdz,
                    const T * __restrict__ dtdz,
                    const T * __restrict__ w3,
                    const int nelv) {
 
  /* One slice per element in the block */
  __shared__ T shu[EB * LX * LX];
 
  /* Element independent, one copy per block */
  __shared__ T shdx[LX * LX];
  __shared__ T shdy[LX * LX];
  __shared__ T shdz[LX * LX];
 
  static_assert(sizeof(shu) + sizeof(shdx) + sizeof(shdy) + sizeof(shdz)
                <= NEKO_EB_MAX_LDS,
                "kstep block exceeds the LDS budget");
 
  /* Threads past the last element still have to reach the barriers in the k
     loop, so clamp their reads and drop their stores rather than returning
     early. At EB == 1 all of this is constant folded away */
  const int eb = (EB == 1) ? 0 : threadIdx.z;
  const int e_blk = blockIdx.x * EB + eb;
  const bool active = (EB == 1) ? true : (e_blk < nelv);
  const int e = active ? e_blk : (nelv - 1);
  const int j = threadIdx.y;
  const int i = threadIdx.x;
  const int ij = i + j * LX;
  const int sh = eb * LX * LX;
  const int ele = e*LX*LX*LX;
 
  if (eb == 0) {
    shdx[ij] = dx[ij];
    shdy[ij] = dy[ij];
    shdz[ij] = dz[ij];
  }
 
  T ru[LX];
 
#pragma unroll LX
  for (int k = 0; k < LX; ++k) {
    ru[k] = u[ij + k*LX*LX + ele];
  }
 
  __syncthreads();
 
  #pragma unroll
  for (int k = 0; k < LX; ++k) {
    const int ijk = ij + k*LX*LX;
    const T W3 = w3[ijk];
    T ttmp = 0.0;
    shu[sh + ij] = ru[k];
#pragma unroll
    for (int l = 0; l < LX; l++) {
      ttmp += shdz[k+l*LX] * ru[l];
    }
    __syncthreads();
 
    T rtmp = 0.0;
    T stmp = 0.0;
#pragma unroll
    for (int l = 0; l < LX; l++) {
      rtmp += shdx[i+l*LX] * shu[sh + l+j*LX];
      stmp += shdy[j+l*LX] * shu[sh + i+l*LX];
    }
 
    if (active) {
      ux[ijk + ele] = W3 * (drdx[ijk + ele] * rtmp
                            + dsdx[ijk + ele] * stmp
                            + dtdx[ijk + ele] * ttmp);
 
      uy[ijk + ele] = W3 * (drdy[ijk + ele] * rtmp
                            + dsdy[ijk + ele] * stmp
                            + dtdy[ijk + ele] * ttmp);
 
      uz[ijk + ele] = W3 * (drdz[ijk + ele] * rtmp
                            + dsdz[ijk + ele] * stmp
                            + dtdz[ijk + ele] * ttmp);
    }
    __syncthreads();
  }
}
 
 
#endif // __MATH_OPGRAD_KERNEL_H__