amg_cheby.cu

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#include <device/device_config.h>
#include <device/cuda/check.h>
 
template< typename T >
__global__ void amg_cheby_solve_part1(T * __restrict__ r,
                                      T * __restrict__ f,
                                      T * __restrict__ w,
                                      T * __restrict__ x,
                                      T * __restrict__ d,
                                      const T inv_thet,
                                      const bool zero_initial,
                                      const int n) {
  const int idx = blockIdx.x * blockDim.x + threadIdx.x;
  const int str = blockDim.x * gridDim.x;
 
  for (int i = idx; i < n; i += str) {
    const real rt = f[i] - (!zero_initial ? w[i] : 0.0);
    const real dt = rt * inv_thet;
    r[i] = rt;
    d[i] = dt;
    x[i] = x[i] + dt;
    
  }
}
 
template< typename T >
__global__ void amg_cheby_solve_part2(T * __restrict__ r,
                                      T * __restrict__ w,
                                      T * __restrict__ d,
                                      T * __restrict__ x,
                                      const T tmp1,
                                      const T tmp2,
                                      const int n) {
  const int idx = blockIdx.x * blockDim.x + threadIdx.x;
  const int str = blockDim.x * gridDim.x;
 
  for (int i = idx; i < n; i += str) {
    const real rt = r[i] - w[i];
    const real dt = tmp1 * d[i] + tmp2 * rt;
    r[i] = rt;
    d[i] = dt;
    x[i] = x[i] + dt;
  }
}
 
extern "C" {
 
  void cuda_amg_cheby_solve_part1(void *r, void *f, void *w, void *x, void *d,
                                 real *inv_thet, int *n, bool *zero_initial,
                                 cudaStream_t strm) {
    const dim3 nthrds(1024, 1, 1);
    const dim3 nblcks(((*n)+1024 - 1)/ 1024, 1, 1);
 
    amg_cheby_solve_part1<real><<<nblcks, nthrds, 0, strm>>>
      ((real *) r, (real *) f, (real *) w, (real *) x, (real *) d,
       *inv_thet, *zero_initial, *n);
    CUDA_CHECK(cudaGetLastError());
  }
 
  void cuda_amg_cheby_solve_part2(void *r, void *w, void *d, void *x,
                                 real *tmp1, real *tmp2, int *n,
                                 cudaStream_t strm) {
 
    const dim3 nthrds(1024, 1, 1);
    const dim3 nblcks(((*n)+1024 - 1)/ 1024, 1, 1);
 
    amg_cheby_solve_part2<real><<<nblcks, nthrds, 0, strm>>>
      ( (real *) r, (real *) w, (real *) d, (real *) x, *tmp1, *tmp2, *n);
    CUDA_CHECK(cudaGetLastError());
  }
 
}