project_005 Vector Addition

#include "cuda_runtime.h"
#include "device_launch_parameters.h"
#include <stdio.h>
#include <cuda.h>


#define SIZE 1024*216

__global__ void add(int* a, int* b, int* c, int N) {
    int index = threadIdx.x + blockIdx.x * blockDim.x;
    c[index] = a[index] + b[index];
    printf("\nHello ");
}



// Function to populate a vector with random integers

void random_ints(int* x, int size) {
    for (int i = 0; i < size; i++) {
        x[i] = rand() % 100;
    }
}


int main(void) {

    int* a, * b, * c; // host copies of a, b, c
    int* d_a, * d_b, * d_c; // device copies of a, b, c
    int size = SIZE * sizeof(int);

    // Allocate space for device copies of a, b, c
    cudaMalloc((void**)&d_a, size);
    cudaMalloc((void**)&d_b, size);
    cudaMalloc((void**)&d_c, size);

    // Allocate space for host copies of a, b, c and setup input values
    a = (int*)malloc(size); random_ints(a, SIZE);
    b = (int*)malloc(size); random_ints(b, SIZE);
    c = (int*)malloc(size);

    // Copy inputs to device
    cudaMemcpy(d_a, a, size, cudaMemcpyHostToDevice);
    cudaMemcpy(d_b, b, size, cudaMemcpyHostToDevice);

    // Create events for timing
    add << <216, 1024 >> > (d_a, d_b, d_c, SIZE);
//    cudaDeviceSynchronize();

    // Copy result back to host
    cudaMemcpy(c, d_c, size, cudaMemcpyDeviceToHost);


    int i = 0;
    for(i=0;i<SIZE;i++)
    {
        printf("\nElement ID = %d   --->  %d + %d = %d",i, a[i], b[i], c[i]);
    }
    // Cleanup
    cudaFree(d_a); cudaFree(d_b); cudaFree(d_c);
    free(a); free(b); free(c);
    return 0;

}