using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace vcsGJMAT
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        //-------------------------------------------------------------------
        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            int i;
            int n = 2;
            double[,] a = new double[3, 4];

            a[0, 0] =  2.0; a[0, 1] = 3.0; a[0, 2] =  1.0; a[0, 3] =  4.0;
            a[1, 0] =  4.0; a[1, 1] = 1.0; a[1, 2] = -3.0; a[1, 3] = -2.0;
            a[2, 0] = -1.0; a[2, 1] = 2.0; a[2, 2] =  2.0; a[2, 3] =  2.0;

            MATGJ(n, a);

            for (i = 0; i <= n; i++)
            {
                Console.WriteLine(i.ToString("0") + ":" + a[i, n + 1].ToString("0.000"));
            }

            //連立一次方程式 [a]{x}={y}の解{x}を求める．a(i,j)=[a|y]を入力する
            //入力                      出力結果
            //[a]={ 2, 3, 1} {y}={ 4}   {x}={ 2}
            //    { 4, 1,-3}     {-2}       {-1}
            //    {-1, 2, 2}     { 2]       { 3}

        }
        //-------------------------------------------------------------------
        private void MATGJ(int n,double[,] a)
        {
            //Gauss-Jordan法による連立一次方程式の解法
            int i,j, k, s;
            double p, d, max, dumy;

            for (k = 0; k <= n; k++)
            {
                max = 0.0;
                s = k;
                for (j = k; j <= n; j++)
                {
                    if (Math.Abs(a[j, k]) > max)
                    {
                        max = Math.Abs(a[j, k]);
                        s = j;
                    }
                }
                for (j = 0; j <= n + 1; j++)
                {
                    dumy = a[k, j];
                    a[k, j] = a[s, j];
                    a[s, j] = dumy;
                }
                p = a[k, k];
                for (j = k; j <= n + 1; j++)
                {
                    a[k, j] = a[k, j] / p;
                }
                for (i = 0; i <= n; i++)
                {
                    if (i != k)
                    {
                        d = a[i, k];
                        for (j = k; j <= n + 1; j++)
                        {
                            a[i, j] = a[i, j] - d * a[k, j];
                        }
                    }
                }
            }
        }
        //-------------------------------------------------------------------

    }
}