【文件属性】：
文件名称：选主元求矩阵逆(C++)
文件大小：17KB
文件格式：DOCX
更新时间：2016-01-17 03:53:32
矩阵的逆C++
使用选主元法求矩阵的逆
#include
#include
#include
#include
using namespace std;
//选主元求矩阵的逆
vector SolveInverseMatrix(vector dt)
{
double inputMatrix[5][5];
int mark = 1;
double detVal = 0.0;
vector outputVal;
vector::iterator ibeg = dt.begin();
for (int i = 0; i < 5; ++i)
{
for (int j = 0; j < 5; ++j)
{
inputMatrix[i][j] = *ibeg;
++ibeg;
}
}
int row[5];
int column[5];
for (int k = 0; k < 5; ++k)
{
double maxVal = 0.0;
for (int i = k; i < 5; ++i)
{
for (int j = k; j < 5; ++j)
{
double elem = abs(inputMatrix[i][j]);
if (elem > maxVal)
{
maxVal = elem;
row[k] = i;
column[k] = j;
}
}
}
try
{
if (row[k] != k)
{
mark = -mark;
int temp = row[k];
swap(inputMatrix[k][0],inputMatrix[temp][0]);
swap(inputMatrix[k][1],inputMatrix[temp][1]);
swap(inputMatrix[k][2],inputMatrix[temp][2]);
swap(inputMatrix[k][3],inputMatrix[temp][3]);
swap(inputMatrix[k][4],inputMatrix[temp][4]);
}
if (column[k] != k)
{
mark = -mark;
int temp = column[k];
swap(inputMatrix[0][k],inputMatrix[0][temp]);
swap(inputMatrix[1][k],inputMatrix[1][temp]);
swap(inputMatrix[2][k],inputMatrix[2][temp]);
swap(inputMatrix[3][k],inputMatrix[3][temp]);
swap(inputMatrix[4][k],inputMatrix[4][temp]);
}
}
catch (exception ex)
{
}
if (abs(maxVal) < 0.0001) return 0;
detVal = inputMatrix[k][k];
inputMatrix[k][k] = 1.0 / inputMatrix[k][k];
for (int j = 0; j < 5; ++j)
{
if(j != k)inputMatrix[k][j] *= inputMatrix[k][k];
inputMatrix[k][j] /= maxVal;
}
for (int i = 0; i < 5; ++i)
{
if (i != k)
{
for (int j = 0; j < 5; ++j)
{
if(j != k)inputMatrix[i][j] = inputMatrix[i][j] - inputMatrix[i][k] * inputMatrix[k][j];
}
}
}
for (int i = 0; i < 5; ++i)
{
if (i != k)
{
inputMatrix[i][k] *= -inputMatrix[k][k];
}
}
}
for (int k = 4; k >= 0; --k)
{
if (column[k] != k)
{
int temp = column[k];
swap(inputMatrix[k][0],inputMatrix[temp][0]);
swap(inputMatrix[k][1],inputMatrix[temp][1]);
swap(inputMatrix[k][2],inputMatrix[temp][2]);
swap(inputMatrix[k][3],inputMatrix[temp][3]);
swap(inputMatrix[k][4],inputMatrix[temp][4]);
}
if (row[k] != k)
{
int temp = row[k];
swap(inputMatrix[0][k],inputMatrix[0][temp]);
swap(inputMatrix[1][k],inputMatrix[1][temp]);
swap(inputMatrix[2][k],inputMatrix[2][temp]);
swap(inputMatrix[3][k],inputMatrix[3][temp]);
swap(inputMatrix[4][k],inputMatrix[4][temp]);
}
}
for (int i = 0; i < 5; ++i)
{
for (int j = 0; j < 5; ++j)
{
outputVal.push_back(inputMatrix[i][j]);
}
}
detVal *= mark; //行列式的值
return outputVal;
}
int main()
{
int count = 0;
vector tempVector;
tempVector.push_back(5);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(5);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(5);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(5);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(0);
tempVector.push_back(5);
vector outputVector = SolveInverseMatrix(tempVector);
vector::iterator ibeg = outputVector.begin();
vector::iterator iend = outputVector.end();
for (;ibeg != iend; ++ibeg)
{
++count;
cout<<*ibeg<<"\t\t";
if (count % 5 == 0)
{
cout<
