   cu_dotProduct<<<dimgrid, dimblock>>>(distance_array_d, force_array_d,
                                        result_array_d, num_vectors);
 
+  cudaError_t err = cudaGetLastError();
+  if (err != cudaSuccess) {
+    printf("CUDA errors: %s\n", cudaGetErrorString(err));
+  }
   // transfer results back to host
   cudaMemcpy(result_array, result_array_d, sizeof(long long) * num_vectors,
              cudaMemcpyDeviceToHost);

 */
#define BLOCK_SIZE 32

__global__ void cu_dotProduct(long long *distance_array_d, long long *force_array_d,
                              long long *result_array_d, long long max) {
  long long x;
  x = blockIdx.x * BLOCK_SIZE + threadIdx.x;

  }
}

__global__ void cu_gen_distance_array(long long *distance_array_d,
                                      long long max) {
  long long x;
  x = blockIdx.x * BLOCK_SIZE + threadIdx.x;
  distance_array_d[x] = (x + 1) % 10;
