private static void jacobi_test01()
//****************************************************************************80
//
// Purpose:
//
// JACOBI_TEST01 tests JACOBI1.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 24 June 2011
//
// Author:
//
// John Burkardt
//
{
List <string> command = new();
List <string> data = new();
int i;
int it;
int j;
const double w = 0.5;
Console.WriteLine("");
Console.WriteLine("JACOBI_TEST01:");
const int it_num = 2000;
const int n = 33;
//
// Set the matrix A.
//
double[] a = Matrix.dif2(n, n);
//
// Determine the right hand side vector B.
//
double[] x_exact = new double[n];
for (i = 0; i < n; i++)
{
double t = i / (double)(n - 1);
x_exact[i] = Math.Exp(t) * (t - 1) * t;
// x_exact[i] = ( double ) ( i + 1 );
}
double[] b = typeMethods.r8mat_mv_new(n, n, a, x_exact);
//
// Set the initial estimate for the solution.
//
double[] x = new double[n];
for (i = 0; i < n; i++)
{
x[i] = 0.0;
}
//
// Allocate plot arrays.
//
double[] m_plot = new double[it_num + 1];
double[] r_plot = new double[it_num + 1];
double[] s_plot = new double[it_num + 1];
double[] x_plot = new double[n * (it_num + 1)];
//
// Initialize plot arrays.
//
r_plot[0] = typeMethods.r8mat_residual_norm(n, n, a, x, b);
m_plot[0] = 1.0;
for (i = 0; i < n; i++)
{
x_plot[i + 0 * n] = x[i];
}
for (j = 0; j <= it_num; j++)
{
s_plot[j] = j;
}
//
// Carry out the iteration.
//
for (it = 1; it <= it_num; it++)
{
double[] x_new = Jacobi.jacobi1(n, a, b, x);
r_plot[it] = typeMethods.r8mat_residual_norm(n, n, a, x_new, b);
//
// Compute the average point motion.
//
m_plot[it] = typeMethods.r8vec_diff_norm_squared(n, x, x_new) / n;
//
// Update the solution
//
for (i = 0; i < n; i++)
{
x[i] = (1.0 - w) * x[i] + w * x_new[i];
}
// r8vec_copy ( n, x_new, x );
for (i = 0; i < n; i++)
{
x_plot[i + 0 * n] = x[i];
}
}
typeMethods.r8vec_print(n, x, "Solution");
//
// Plot the residual.
//
double[] rl_plot = new double[it_num + 1];
for (j = 0; j <= it_num; j++)
{
rl_plot[j] = Math.Log(r_plot[j]);
}
//
// Create the data file.
//
string data_filename = "residual_data.txt";
for (j = 0; j <= it_num; j++)
{
data.Add(j + " "
+ rl_plot[j] + "");
}
File.WriteAllLines(data_filename, data);
Console.WriteLine(" ");
Console.WriteLine(" Data stored in \"" + data_filename + "\".");
//
// Create the command file.
//
string command_filename = "residual_commands.txt";
command.Add("# residual_commands.txt");
command.Add("#");
command.Add("# Usage:");
command.Add("# gnuplot < residual_commands.txt");
command.Add("#");
command.Add("set term png");
command.Add("set output 'residual.png'");
command.Add("set style data lines");
command.Add("set xlabel 'Iteration'");
command.Add("set ylabel 'Residual'");
command.Add("set title 'Log(Residual) over Iterations'");
command.Add("set grid");
command.Add("plot 'residual_data.txt' using 1:2 lw 2");
command.Add("quit");
File.WriteAllLines(command_filename, command);
Console.WriteLine(" Plot commands stored in \"" + command_filename + "\".");
//
// Plot the average point motion.
//
double[] ml_plot = new double[it_num + 1];
for (j = 0; j <= it_num; j++)
{
ml_plot[j] = Math.Log(m_plot[j]);
}
//
// Create the data file.
//
data_filename = "motion_data.txt";
data.Clear();
for (j = 0; j <= it_num; j++)
{
data.Add(j + " "
+ ml_plot[j] + "");
}
File.WriteAllLines(data_filename, data);
Console.WriteLine(" ");
Console.WriteLine(" Data stored in \"" + data_filename + "\".");
//
// Create the command file.
//
command_filename = "motion_commands.txt";
command.Clear();
command.Add("# motion_commands.txt");
command.Add("#");
command.Add("# Usage:");
command.Add("# gnuplot < motion_commands.txt");
command.Add("#");
command.Add("set term png");
command.Add("set output 'motion.png'");
command.Add("set style data lines");
command.Add("set xlabel 'Iteration'");
command.Add("set ylabel 'Motion'");
command.Add("set title 'Log(Motion) over Iterations'");
command.Add("set grid");
command.Add("plot 'motion_data.txt' using 1:2 lw 2");
command.Add("quit");
File.WriteAllLines(command_filename, command);
//
// Plot the evolution of the locations of the generators.
//
//figure ( 3 )
//y = ( 0 : it_num );
//for k = 1 : n
// plot ( x_plot(k,1:it_num+1), y )
// hold on;
//end
//grid on
//hold off;
//title ( "Generator evolution." );
//xlabel ( "Generator positions" );
//ylabel ( "Iterations" );
}