Pthreads矩阵-向量程序C语言

以下是一个使用Pthreads实现的矩阵-向量程序的C语言代码：

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#define NUM_THREADS 4
#define MATRIX_SIZE 1000

int matrix[MATRIX_SIZE][MATRIX_SIZE];
int vector[MATRIX_SIZE];
int result[MATRIX_SIZE];
int chunk_size;

void *matrix_vector_multiply(void *thread_id) {
    int tid = *(int*)thread_id;
    int start = tid * chunk_size;
    int end = start + chunk_size;
    for (int i = start; i < end; i++) {
        int sum = 0;
        for (int j = 0; j < MATRIX_SIZE; j++) {
            sum += matrix[i][j] * vector[j];
        }
        result[i] = sum;
    }
    pthread_exit(NULL);
}

int main() {
    pthread_t threads[NUM_THREADS];
    int thread_ids[NUM_THREADS];

    // Initialize matrix and vector
    for (int i = 0; i < MATRIX_SIZE; i++) {
        for (int j = 0; j < MATRIX_SIZE; j++) {
            matrix[i][j] = rand() % 10;
        }
        vector[i] = rand() % 10;
    }

    // Divide the work among the threads
    chunk_size = MATRIX_SIZE / NUM_THREADS;

    // Create threads
    for (int i = 0; i < NUM_THREADS; i++) {
        thread_ids[i] = i;
        pthread_create(&threads[i], NULL, matrix_vector_multiply, &thread_ids[i]);
    }

    // Wait for threads to finish
    for (int i = 0; i < NUM_THREADS; i++) {
        pthread_join(threads[i], NULL);
    }

    // Print result vector
    printf("Result vector:\n");
    for (int i = 0; i < MATRIX_SIZE; i++) {
        printf("%d ", result[i]);
    }
    printf("\n");

    return 0;
}

该程序将矩阵和向量初始化为随机值，然后将矩阵乘以向量，将结果存储在result数组中。程序使用pthread_create函数创建线程，并使用pthread_join函数等待线程完成。每个线程计算矩阵的一部分，以便并行执行。程序使用一个chunk_size变量来确定每个线程需要处理的矩阵的行数。