private static void diffusivity_1d_xk_test()
//****************************************************************************80
//
// Purpose:
//
// diffusivity_1d_xk_test tests diffusivity_1d_xk.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 07 August 2013
//
// Author:
//
// John Burkardt
//
// Reference:
//
// Dongbin Xiu, George Karniadakis,
// Modeling uncertainty in steady state diffusion problems via
// generalized polynomial chaos,
// Computer Methods in Applied Mechanics and Engineering,
// Volume 191, 2002, pages 4927-4948.
//
{
string command_filename = "diffusivity_1d_xk_commands.txt";
List <string> command_unit = new();
string data_filename = "diffusivity_1d_xk_data.txt";
List <string> data_unit = new();
Console.WriteLine("");
Console.WriteLine("diffusivity_1d_xk_test");
Console.WriteLine(" Plot the stochastic diffusivity function");
Console.WriteLine(" defined by diffusivity_1d_xk.");
//
// Set up the spatial grid.
//
int n = 51;
double x_min = -1.0;
double x_max = +1.0;
double[] x = typeMethods.r8vec_linspace_new(n, x_min, x_max);
//
// Sample the OMEGA values.
//
int m = 5;
int seed = 123456789;
typeMethods.r8vecNormalData data = new();
double[] omega = typeMethods.r8vec_normal_01_new(m, ref data, ref seed);
//
// Compute the diffusivity field.
//
double dc0 = 10.0;
double[] dc = Stochastic.diffusivity_1d_xk(dc0, m, omega, n, x);
//
// Create data file.
//
for (int j = 0; j < n; j++)
{
data_unit.Add(" " + x[j].ToString(CultureInfo.InvariantCulture).PadLeft(14)
+ " " + dc[j].ToString(CultureInfo.InvariantCulture).PadLeft(14) + "");
}
File.WriteAllLines(data_filename, data_unit);
Console.WriteLine("");
Console.WriteLine(" Created graphics data file '" + data_filename + "'");
//
// Create the command file.
//
double dc_max = typeMethods.r8vec_max(n, dc);
command_unit.Add("# " + command_filename + "");
command_unit.Add("#");
command_unit.Add("# Usage:");
command_unit.Add("# gnuplot < " + command_filename + "");
command_unit.Add("#");
command_unit.Add("set term png");
command_unit.Add("set output 'diffusivity_1d_xk.png'");
command_unit.Add("set xlabel '<---X--->'");
command_unit.Add("set ylabel '<---DC(X)--->'");
command_unit.Add("set yrange [0.0:" + dc_max + "]");
command_unit.Add("set title 'XK Stochastic diffusivity function'");
command_unit.Add("set grid");
command_unit.Add("set style data lines");
command_unit.Add("plot '" + data_filename + "' using 1:2 lw 3 linecolor rgb 'red'");
File.WriteAllLines(command_filename, command_unit);
Console.WriteLine(" Created graphics command file '" + command_filename + "'");
}
