VectorAdd.c

// MP 1
#include <wb.h>

__global__ void vecAdd(float *in1, float *in2, float *out, int len) {
  //@@ Insert code to implement vector addition here
  int i = threadIdx.x + blockDim.x * blockIdx.x;
   if (i<len){ out[i] = in1[i] + in2[i]; }
}

int main(int argc, char **argv) {
  wbArg_t args;
  int inputLength;
  float *hostInput1;
  float *hostInput2;
  float *hostOutput;
  float *deviceInput1;
  float *deviceInput2;
  float *deviceOutput;

  args = wbArg_read(argc, argv);

  wbTime_start(Generic, "Importing data and creating memory on host");
  hostInput1 =
      (float *)wbImport(wbArg_getInputFile(args, 0), &inputLength);
  hostInput2 =
      (float *)wbImport(wbArg_getInputFile(args, 1), &inputLength);
  hostOutput = (float *)malloc(inputLength * sizeof(float));
  wbTime_stop(Generic, "Importing data and creating memory on host");

  wbLog(TRACE, "The input length is ", inputLength);

  wbTime_start(GPU, "Allocating GPU memory.");
  //@@ Allocate GPU memory here
  cudaMalloc((void **) &deviceOutput, inputLength * sizeof(float));
  cudaMalloc((void **) &deviceInput1, inputLength * sizeof(float));
	cudaMalloc((void **) &deviceInput2, inputLength * sizeof(float));

  wbTime_stop(GPU, "Allocating GPU memory.");

  wbTime_start(GPU, "Copying input memory to the GPU.");
  //@@ Copy memory to the GPU here
	cudaMemcpy(deviceInput1, hostInput1, inputLength * sizeof(float), cudaMemcpyHostToDevice);
	cudaMemcpy(deviceInput2, hostInput2, inputLength * sizeof(float), cudaMemcpyHostToDevice);

  wbTime_stop(GPU, "Copying input memory to the GPU.");

  //@@ Initialize the grid and block dimensions here
	dim3 DimGrid(inputLength/256, 1, 1);
	if(inputLength%256) DimGrid.x++;
	dim3 DimBlock(256, 1, 1);

  wbTime_start(Compute, "Performing CUDA computation");
  //@@ Launch the GPU Kernel here
	vecAdd<<<DimGrid, DimBlock>>>(deviceInput1, deviceInput2, deviceOutput, inputLength);

  cudaDeviceSynchronize();
  wbTime_stop(Compute, "Performing CUDA computation");

  wbTime_start(Copy, "Copying output memory to the CPU");
  //@@ Copy the GPU memory back to the CPU here
	cudaMemcpy(hostOutput, deviceOutput, inputLength * sizeof(float), cudaMemcpyDeviceToHost);

  wbTime_stop(Copy, "Copying output memory to the CPU");

  wbTime_start(GPU, "Freeing GPU Memory");
  //@@ Free the GPU memory here
	cudaFree(deviceInput1);
	cudaFree(deviceInput2);
	cudaFree(deviceOutput);

  wbTime_stop(GPU, "Freeing GPU Memory");

  wbSolution(args, hostOutput, inputLength);

  free(hostInput1);
  free(hostInput2);
  free(hostOutput);

  return 0;
}