簡述

矩陣向量乘法。

• 讀取文件data.txt
• 并輸入到output.txt文件中
• 用typedef方便的修改數據類型（要是寫成模板也是可以的）

代碼

#include "cuda_runtime.h" #include "device_launch_parameters.h" #include <iostream> #include <fstream> #include <iomanip> #include <stdio.h>typedef double DATA;// Kernal: __global__ void MatrixMultiply(DATA *a, DATA * b, DATA *c, int N) {int tx = threadIdx.x + blockIdx.x * blockDim.x;if (tx < N) {DATA sum = 0;for (int k = 0; k < N; ++k) {sum += a[tx * N + k] * b[k];}c[tx] = sum;} }cudaError_t matrixMultiplyWithCuda(DATA *a, DATA *b, DATA *c, size_t size);int main() {std::ifstream in("data.txt");int N;in >> N;if (in.fail()) {printf("Something wrong\n");}else {printf("Success read\n");}// host initialDATA *a = new DATA[N * N];DATA *b = new DATA[N];DATA *c = new DATA[N];// read for (int i = 0; i < N; ++i)for (int j = 0; j < N; ++j) in >> a[i * N + j];for (int i = 0; i < N; ++i) in >> b[i];cudaError_t cudaStatus = matrixMultiplyWithCuda(a, b, c, N);std::ofstream out("output.txt");for (int i = 0; i < N; ++i) {out << std::setiosflags(std::ios::fixed) << c[i] << " ";out << std::endl;}cudaStatus = cudaThreadExit();// host free delete[] a;delete[] b;delete[] c;return 0; } cudaError_t matrixMultiplyWithCuda(DATA *a, DATA *b, DATA *c, size_t N) {DATA *dev_a = 0;DATA *dev_b = 0;DATA *dev_c = 0;cudaError_t cudaStatus;cudaStatus = cudaMalloc((void**)&dev_a, N * N * sizeof(DATA));cudaStatus = cudaMalloc((void**)&dev_b, N * sizeof(DATA));cudaStatus = cudaMalloc((void**)&dev_c, N * sizeof(DATA));cudaStatus = cudaMemcpy(dev_a, a, N * N * sizeof(DATA), cudaMemcpyHostToDevice);cudaStatus = cudaMemcpy(dev_b, b, N * sizeof(DATA), cudaMemcpyHostToDevice);if (cudaStatus != cudaSuccess) {printf("Something wrong\n");goto Error;}// kernal invocation dim3 threadPerBlock(500, 1, 1);dim3 numBlocks(N / threadPerBlock.x+1, 1, 1);MatrixMultiply<<<numBlocks, threadPerBlock>>>(dev_a, dev_b, dev_c, N);if (cudaStatus != cudaSuccess) {printf( "Calculate wrong\n");goto Error;}cudaStatus = cudaMemcpy(c, dev_c, N * sizeof(DATA), cudaMemcpyDeviceToHost); Error:cudaFree(dev_a);cudaFree(dev_b);cudaFree(dev_c);return cudaStatus; }

總結

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