Jinhong_Homework3/task3.cpp

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

#define SIZE 102
void matmul(float** A, float** B, float** C, int n)
{
	for (int i = 0; i < n; ++i) 
	{	
		for (int j = 0; j < n; ++j) 
		{
			C[i][j] = 0;
			for (int k = 0; k < n; ++k) 
			{	
				C[i][j] += A[i][k] * B[k][j];
			}
		}
	}
}
int main()
{
	srand(time(NULL));
	
	// 分配矩阵内存
    float** A = (float**)malloc(SIZE * sizeof(float*));
    float** B = (float**)malloc(SIZE * sizeof(float*));
    float** C = (float**)malloc(SIZE * sizeof(float*));
    for (int i = 0; i < SIZE; ++i) 
    {
        A[i] = (float*)malloc(SIZE * sizeof(float));
        B[i] = (float*)malloc(SIZE * sizeof(float));
        C[i] = (float*)malloc(SIZE * sizeof(float));
    }
	
	//初始化矩阵数据
	for (int i = 0; i < SIZE; i++) 
	{
		for(int j=0;j<SIZE;j++)
		{
			A[i][j] = (float)(rand() % 100) / 100.0f;
       	 	B[i][j] = (float)(rand() % 100) / 100.0f;
		}
        
    }
    
    clock_t start = clock();
    matmul(A, B, C, SIZE);
    clock_t end = clock();

    // 计算并输出向量乘法的时间
    double multiply_time_spent = double(end - start) / CLOCKS_PER_SEC;
    printf("使用基础的向量乘法：\n当SIZE取%d时，初始向量乘法时间：%lf秒\n", SIZE,multiply_time_spent);
    
    // 释放动态分配的内存
    for (int i = 0; i < SIZE; ++i) {
        free(A[i]);free(B[i]);free(C[i]);
    }
    free(A);free(B);free(C);

}