矩阵乘法

最新推荐文章于 2025-10-10 19:48:18 发布

原创最新推荐文章于 2025-10-10 19:48:18 发布 · 620 阅读

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CC 4.0 BY-SA版权

本文详细介绍了如何实现并调用矩阵乘法函数，包括代码解析、调用方式以及实例演示。

矩阵乘法本身逻辑简单，实现这个函数却用了个吧小时，现将参考代码分享如下：

//矩阵乘法 此函数实现double型矩阵乘法 其他类型可以使用模板 或将double修改为其他类型
void Matrix_Multiplication_d(double* mA, int aM, int aN, double* mB, int bM, int bN, double* mR)
{
	if (aN != bM || mA==NULL || mB==NULL || mR==NULL)
	{
		return;
	}

	int iTemp0 = 0;
	int index0 = 0;
	int index1 = 0;

	double *sum = (double*)malloc(bN*sizeof(double));

	if( sum == NULL )
	{
		return;
	}

	//循环处理矩阵A每一行
	for (int am=0; am<aM; am++)
	{	
		memset(sum, 0, sizeof(double)*bN);
		//矩阵B
		for (int bm=0; bm<bM; bm++)
		{
			iTemp0 = bm*bN;		
		
			for (int bn=0; bn<bN; bn++)
			{
				index0 = iTemp0 + bn;	
				index1 = am*aN + bm;  //计算矩阵A对应位置		
				
				if (bm == 0)
				{
					sum[bn] = mB[index0]*mA[index1];
				}
				else
				{
					sum[bn] += mB[index0]*mA[index1];
				}				
			}
		}	

		memcpy(mR+am*bN, sum, sizeof(double)*bN);
	}

	free(sum);
}

调用方式

int _tmain(int argc, _TCHAR* argv[])
{
	//一维数组
	double mA[16] = {1,2,3,4,  5,6,7,8,  9,10,11,12,  13,14,15,16};
	double mB[16] = {1,2,3,4,  5,6,7,8,  9,10,11,12,  13,14,15,16};
	double mR[16] = {0};

	Matrix_Multiplication_d(mA, 4, 4, mB, 4, 4, mR);

	for (int i=0 ;i<16; i++)
	{
		cout<<mR[i]<<"  ";

		if ((i+1)%4 == 0)
		{
			cout<<endl;
		}
	}
	cout<<endl;

	//二维数组
	double mA1[4][4] = {{1,2,3,4} , {5,6,7,8} , {9,10,11,12} , {13,14,15,16}};
	double mB1[4][4] = {{1,2,3,4} , {5,6,7,8}  ,{9,10,11,12} , {13,14,15,16}};
	double mR1[4][4] = {0};

	Matrix_Multiplication_d(&mA1[0][0], 4, 4, &mB1[0][0], 4, 4, &mR1[0][0]);

	for (int n=0; n<4; n++)
	{
		for (int m=0; m<4; m++)
		{
			cout<<mR1[n][m]<<"  ";
		}
		cout<<endl;
	}

	return 0;
}