#ifndef _CUDA_UTILS_H
#define _CUDA_UTILS_H

#include <ATen/ATen.h>
#include <ATen/cuda/CUDAContext.h>
#include <cmath>

#include <cuda.h>
#include <cuda_runtime.h>

#include <vector>

#define MAXIMUM_THREADS 512

inline int optimal_num_threads(int work_size) {
  const int pow_2 = std::log2(static_cast<double>(work_size));
  return max(min(1 << pow_2, MAXIMUM_THREADS), 1);
}

inline dim3 optimal_block_config(int x, int y) {
  const int x_threads = optimal_num_threads(x);
  const int y_threads =
      max(min(optimal_num_threads(y), MAXIMUM_THREADS / x_threads), 1);
  dim3 block_config(x_threads, y_threads, 1);
  return block_config;
}

#define CUDA_CHECK_ERRORS()                                                    \
  {                                                                            \
    cudaError_t err = cudaGetLastError();                                      \
    if (cudaSuccess != err) {                                                  \
      fprintf(stderr, "CUDA kernel failed : %s\n%s at L:%d in %s\n",           \
              cudaGetErrorString(err), __PRETTY_FUNCTION__, __LINE__,          \
              __FILE__);                                                       \
      exit(-1);                                                                \
    }                                                                          \
  }

#endif