mymatrix.cpp

GaussJordan消去法C++实现

// myMatrix.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "iostream.h"
#include "malloc.h"

int Row=0,Col=0;//矩阵总行数,总列数

double * InitMatrix()
{
	double * matrix;
	cout<<"  请输入矩阵维数(行,列):"<<endl;
	cin>>Row>>Col;
	matrix = (double*)malloc(Row*Col*sizeof(double));
	double * Elem;
	Elem = matrix;
	cout<<"  请依次输入行列元素值:"<<endl;
	for(int i=0;i<Row;i++)
	{
		for(int j=0;j<Col;j++)
		{
			cout<<" mat("<<i<<","<<j<<")=";
			cin>>*Elem;
			Elem++;
		}
	}
	return matrix;
}

double GetElem(double * mat,int m,int n)
{
	double *Elem = mat;
	int i=0;
	while(i<(m*Col+n))
	{
		Elem++;
		i++;
	}
	return *Elem;
}

void SetElem(double * mat,int m,int n,double v)
{
	double *Elem = mat;
	int i=0;
	while(i<(m*Col+n))
	{
		Elem++;
		i++;
	}
	*Elem = v;
}

bool GaussJordan(double * mat)
{
	if(1 != (Col-Row))
		return false;
	int i = 0,j = 0,k = 0;//行标，列标,第几轮计算
	double L_ik = 1;
	double L_kk = 1;//Elem(k,k)的倒数
	double matElem = 0;

	for(k = 0;k < Row;k++)
	{
		if(0 == GetElem(mat,k,k))
			return false;
		L_kk = 1/GetElem(mat,k,k);
		for(i = 0;i < Row;i++)
		{					
			if(i == k)
				continue;					
			L_ik = GetElem(mat,i,k)*L_kk;
			for(j = k+1;j < Col;j++)
			{
				matElem = GetElem(mat,i,j) - L_ik * GetElem(mat,k,j);
				SetElem(mat,i,j,matElem);
			}					
		}
		//计算主行
		for(j = k;j < Col;j++)
		{
			matElem = L_kk * GetElem(mat,k,j);
			SetElem(mat,k,j,matElem);
		}
	}
	//构造结果解矩阵
	cout<<"计算结果如下:"<<endl;
	for(i = 0;i < Row;i++)
	{
		cout<<"\t"<<GetElem(mat,i,Row); 
	}
	return true;
}

int main(int argc, char* argv[])
{
	double * mat = InitMatrix();
	if(!GaussJordan(mat))
	{
		cout<<"错误!"<<endl;
	}
	return 0;
}