Pthreads实现矩阵向量乘法。
时间: 2024-02-19 07:59:28 浏览: 19
好的,下面给您介绍一下使用Pthreads实现矩阵向量乘法的方法:
首先,我们需要定义一个结构体,用于传递参数:
```
typedef struct {
double *matrix; // 矩阵
double *vector; // 向量
double *result; // 结果
int rows; // 矩阵的行数
int cols; // 矩阵的列数
int start; // 起始行
int end; // 结束行
} thread_param_t;
```
然后,我们需要编写一个线程函数,用于计算矩阵向量乘法:
```
void *multiply(void *arg) {
thread_param_t *param = (thread_param_t *)arg;
for (int i = param->start; i < param->end; i++) {
double sum = 0.0;
for (int j = 0; j < param->cols; j++) {
sum += param->matrix[i * param->cols + j] * param->vector[j];
}
param->result[i] = sum;
}
pthread_exit(NULL);
}
```
接下来,我们需要创建线程,并将参数传递给它们:
```
void multiply_matrix_vector(double *matrix, double *vector, double *result, int rows, int cols, int num_threads) {
pthread_t threads[num_threads];
thread_param_t params[num_threads];
int rows_per_thread = rows / num_threads;
for (int i = 0; i < num_threads; i++) {
params[i].matrix = matrix;
params[i].vector = vector;
params[i].result = result;
params[i].rows = rows;
params[i].cols = cols;
params[i].start = i * rows_per_thread;
params[i].end = (i == num_threads - 1) ? rows : (i + 1) * rows_per_thread;
pthread_create(&threads[i], NULL, multiply, (void *)¶ms[i]);
}
for (int i = 0; i < num_threads; i++) {
pthread_join(threads[i], NULL);
}
}
```
最后,我们可以调用 multiply_matrix_vector() 函数来进行矩阵向量乘法计算:
```
int main() {
double matrix[4][3] = {{1.0, 2.0, 3.0}, {4.0, 5.0, 6.0}, {7.0, 8.0, 9.0}, {10.0, 11.0, 12.0}};
double vector[3] = {1.0, 2.0, 3.0};
double result[4] = {0.0};
multiply_matrix_vector((double *)matrix, vector, result, 4, 3, 2);
for (int i = 0; i < 4; i++) {
printf("%lf ", result[i]);
}
printf("\n");
return 0;
}
```
以上就是使用 Pthreads 实现矩阵向量乘法的方法,希望对您有所帮助!