C实现任意阶矩阵求逆矩阵

#include <QtCore/QCoreApplication> #include <iostream> #include <math.h> #define n 3 int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); /*double matrix[n][n]={127187.37,1192236.059,89741.8184,1277187.37,8718.368, 1192236.059,1163344.333,82741.555,85377.455,9416.8109, 89741.8184,82741.55522,107440.1425,8718.368,124.058, 82741.555,85377.455,8718.368,9416.8109,1359.0965, 8718.3682,9416.8109,1240.58,1359.09,0};*/ long double matrix[n][n] = {1,0,0,1,0,0,1,0,0}; long double E_Matrix[n][n]; long double mik; long double m = 2*n; for(int i = 0; i < n; i++) { for(int j = 0; j < n; j++) { if(i == j) E_Matrix[i][j] = 1.00; else E_Matrix[i][j] = 0.00; } } long double CalcuMatrix[n][2*n]; for(int i = 0; i < n; i++) { for(int j = 0; j < n; j++) { CalcuMatrix[i][j] = matrix[i][j]; } for(int k = n; k < m; k++) { CalcuMatrix[i][k] = E_Matrix[i][k-n]; } } for(int i = 1; i <= n-1; i++) { for(int j = i+1; j <= n; j++) { mik = CalcuMatrix[j-1][i-1]/CalcuMatrix[i-1][i-1]; for(int k = i+1;k <= m; k++) { CalcuMatrix[j-1][k-1] -= mik*CalcuMatrix[i-1][k-1]; } } } for(int i=1;i<=n;i++) { double temp = CalcuMatrix[i-1][i-1]; for(int j=1;j<=m;j++) { CalcuMatrix[i-1][j-1] = CalcuMatrix[i-1][j-1]/temp; } } for(int k=n-1;k>=1;k--) { for(int i=k;i>=1;i--) { mik = CalcuMatrix[i-1][k]; for(int j=k+1;j<=m;j++) { CalcuMatrix[i-1][j-1] -= mik*CalcuMatrix[k][j-1]; } } } long double InverseMatrix[n][n]; for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { InverseMatrix[i][j] = CalcuMatrix[i][j+n]; } } for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { if(fabs(InverseMatrix[i][j]) < 0.0000001) InverseMatrix[i][j] = 0.00; } } for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { printf("%5.9f\t",InverseMatrix[i][j]); } printf("\n"); } return a.exec(); }