Gauss-Jordan 掃き出し法

gauss-jordan.cc

#include <bits/stdc++.h>
using namespace std;

void printmatrix(double a[10][11], int n) {
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n+1; ++j) {
			cout << a[i][j] << " ";
		}
		cout << endl;
	}
	cout << endl;
}

void gaussjordan(double a[10][11], int n) {
	for (int k = 0; k < n; ++k) {
		printmatrix(a, n);
		double w1 = a[k][k];
		for(int j = k; j <= n; ++j) {
			a[k][j] = a[k][j]/w1;
		}
		for (int i = 0; i <= n; ++i) {
			double w2 = a[i][k];
			if (i != k) {
				for (int j = k; j <= n; ++j) {
					a[i][j] = a[i][j] - w2*a[k][j];
				}
			}
		}
	}
}

int main() {
	double a[10][11] = {
		{  2,  -2,  3,  1,  },
		{  1,  1,  -6,  -1,  },
		{  3,  -2,  4, 4,  },
	};
	int n = 3;
	gaussjordan(a, n);
	printmatrix(a, n);
	return 0;
}