cuda and c++ problem

Question

hi i have a cuda program which run successfully here is code for cuda program

#include <stdio.h>
#include <cuda.h>

    __global__ void square_array(float *a, int N)
    {
      int idx = blockIdx.x * blockDim.x + threadIdx.x;
      if (idx<N) 
       a[idx] = a[idx] * a[idx];
    }

    int main(void)
    {
      float *a_h, *a_d; 
      const int N = 10;  
      size_t size = N * sizeof(float);
      a_h = (float *)malloc(size);        
      cudaMalloc((void **) &a_d, size);   
      for (int i=0; i<N; i++) a_h[i] = (float)i;
      cudaMemcpy(a_d, a_h, size, cudaMemcpyHostToDevice);
      int block_size = 4;
      int n_blocks = N/block_size + (N%block_size == 0 ? 0:1);
      square_array <<< n_blocks, block_size >>> (a_d, N);

      cudaMemcpy(a_h, a_d, sizeof(float)*N, cudaMemcpyDeviceToHost);
      // Print results
      for (int i=0; i<N; i++) printf("%d %f\n", i, a_h[i]);

      free(a_h); 
      cudaFree(a_d);
    }

now i want to split this code into two files means there should be two file one for c++ code or c code and other one .cu file for kernel. i just wanat to do it for learning and i don't want to write same kernel code again and again. can any one tell me how to do this ? how to split this code into two different file? than how to compile it? how to write makefile for it ? how to

Answer 1

Code which has CUDA C extensions has to be in *.cu file, rest can be in c++ file.

So here your kernel code can be moved to separate *.cu file.

To have main function implementation in c++ file you need to wrap invocation of kernel (code with square_array<<<...>>>(...);) with c++ function which implementation needs to be in *cu file as well.

Functions cudaMalloc etc. can be left in c++ file as long as you include proper cuda headers.