helloCUDA_input_test.cu

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

__global__ void vectorAdd(const float *A, const float *B, float *C, int numElements)
{
    int i = blockDim.x * blockIdx.x + threadIdx.x;

    if (i < numElements)
    {
        C[i] = A[i] + B[i];
    }
}

int main(void)
{
    // Error code to check return values for CUDA calls
    cudaError_t err = cudaSuccess;

    // Print the vector length to be used, and compute its size
    int numElements = 0;
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&numElements);

        size_t size = numElements * sizeof(float);
        //printf("[Vector addition of %d elements]\n", numElements);

        // Allocate the host input vector A
        float *h_A = (float *)malloc(size);

        // Allocate the host input vector B
        float *h_B = (float *)malloc(size);

        // Allocate the host output vector C
        float *h_C = (float *)malloc(size);

        // Verify that allocations succeeded
        if (h_A == NULL || h_B == NULL || h_C == NULL)
        {
            fprintf(stderr, "Failed to allocate host vectors!\n");
            exit(EXIT_FAILURE);
        }

        // Initialize the host input vectors
        for (int i = 0; i < numElements; ++i)
        {
            scanf("%f",&h_A[i]);
         
        }
        for (int i = 0; i < numElements; ++i)
        {
         
            scanf("%f",&h_B[i]);
        }

        
        // Allocate the device input vector A
        float *d_A = NULL;
        err = cudaMalloc((void **)&d_A, size);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to allocate device vector A (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        // Allocate the device input vector B
        float *d_B = NULL;
        err = cudaMalloc((void **)&d_B, size);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to allocate device vector B (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        // Allocate the device output vector C
        float *d_C = NULL;
        err = cudaMalloc((void **)&d_C, size);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to allocate device vector C (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        // Copy the host input vectors A and B in host memory to the device input vectors in
        // device memory
       // printf("Copy input data from the host memory to the CUDA device\n");
        err = cudaMemcpy(d_A, h_A, size, cudaMemcpyHostToDevice);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to copy vector A from host to device (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        err = cudaMemcpy(d_B, h_B, size, cudaMemcpyHostToDevice);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to copy vector B from host to device (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        // Launch the Vector Add CUDA Kernel
        int threadsPerBlock = 256;
        int blocksPerGrid =(numElements + threadsPerBlock - 1) / threadsPerBlock;
        //printf("CUDA kernel launch with %d blocks of %d threads\n", blocksPerGrid, threadsPerBlock);
        vectorAdd<<<blocksPerGrid, threadsPerBlock>>>(d_A, d_B, d_C, numElements);
        err = cudaGetLastError();

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to launch vectorAdd kernel (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        // Copy the device result vector in device memory to the host result vector
        // in host memory.
       // printf("Copy output data from the CUDA device to the host memory\n");
        err = cudaMemcpy(h_C, d_C, size, cudaMemcpyDeviceToHost);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to copy vector C from device to host (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        // Verify that the result vector is correct
        for (int i = 0; i < numElements; ++i)
        {
            if (fabs(h_A[i] + h_B[i] - h_C[i]) > 1e-5)
            {
                fprintf(stderr, "Result verification failed at element %d!\n", i);
                exit(EXIT_FAILURE);
            }
        }

       // printf("Test PASSED\n");

        // Free device global memory
        err = cudaFree(d_A);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to free device vector A (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        err = cudaFree(d_B);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to free device vector B (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        err = cudaFree(d_C);

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to free device vector C (error code %s)!\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }

        
        // Reset the device and exit
        // cudaDeviceReset causes the driver to clean up all state. While
        // not mandatory in normal operation, it is good practice.  It is also
        // needed to ensure correct operation when the application is being
        // profiled. Calling cudaDeviceReset causes all profile data to be
        // flushed before the application exits
        err = cudaDeviceReset();

        if (err != cudaSuccess)
        {
            fprintf(stderr, "Failed to deinitialize the device! error=%s\n", cudaGetErrorString(err));
            exit(EXIT_FAILURE);
        }
        for (int i = 0; i < numElements; ++i)
        {
            printf("%.2f ",h_C[i]);
        }       
        printf("\n");
	// Free host memory
        free(h_A);
        free(h_B);
        free(h_C);

        //printf("Done\n");
    
    }
    return 0;
}