private static void Main(string[] args)
//****************************************************************************80
//
// Purpose:
//
// MAIN is the main program for LAGUERRE_RULE_SS.
//
// Discussion:
//
// This program computes a standard or exponentially weighted
// Gauss-Laguerre quadrature rule and writes it to a file.
//
// The user specifies:
// * the ORDER (number of points) in the rule
// * the OPTION (standard or reweighted rule)
// * the root name of the output files.
//
// The parameter A is meant to represent the left endpoint of the interval
// of integration, and is currently fixed at 0. It might be useful to allow
// the user to input a nonzero value of A. In that case, the weights and
// abscissa would need to be appropriately adjusted.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 20 February 2008
//
// Author:
//
// John Burkardt
//
{
const double a = 0.0;
int option;
int order;
string output;
Console.WriteLine("");
Console.WriteLine("");
Console.WriteLine("LAGUERRE_RULE_SS");
Console.WriteLine("");
Console.WriteLine(" Compute a Gauss-Laguerre rule for approximating");
Console.WriteLine("");
Console.WriteLine(" Integral ( A <= x < +oo ) exp(-x) f(x) dx");
Console.WriteLine("");
Console.WriteLine(" of order ORDER.");
Console.WriteLine("");
Console.WriteLine(" For now, A is fixed at 0.0.");
Console.WriteLine("");
Console.WriteLine(" The user specifies ORDER, OPTION, and OUTPUT.");
Console.WriteLine("");
Console.WriteLine(" OPTION is:");
Console.WriteLine("");
Console.WriteLine(" 0 to get the standard rule for handling:");
Console.WriteLine(" Integral ( A <= x < +oo ) exp(-x) f(x) dx");
Console.WriteLine("");
Console.WriteLine(" 1 to get the modified rule for handling:");
Console.WriteLine(" Integral ( A <= x < +oo ) f(x) dx");
Console.WriteLine("");
Console.WriteLine(" For OPTION = 1, the weights of the standard rule");
Console.WriteLine(" are multiplied by exp(+x).");
Console.WriteLine("");
Console.WriteLine(" OUTPUT is:");
Console.WriteLine("");
Console.WriteLine(" \"C++\" for printed C++ output;");
Console.WriteLine(" \"F77\" for printed Fortran77 output;");
Console.WriteLine(" \"F90\" for printed Fortran90 output;");
Console.WriteLine(" \"MAT\" for printed MATLAB output;");
Console.WriteLine("");
Console.WriteLine(" or:");
Console.WriteLine("");
Console.WriteLine(" \"filename\" to generate 3 files:");
Console.WriteLine("");
Console.WriteLine(" filename_w.txt - the weight file");
Console.WriteLine(" filename_x.txt - the abscissa file.");
Console.WriteLine(" filename_r.txt - the region file.");
//
// Get the order.
//
try
{
order = Convert.ToInt32(args[0]);
}
catch
{
Console.WriteLine("");
Console.WriteLine(" Enter the value of ORDER (1 or greater)");
order = Convert.ToInt32(Console.ReadLine());
}
Console.WriteLine("");
Console.WriteLine(" The requested order of the rule is = " + order + "");
//
// Get the option.
//
try
{
option = Convert.ToInt32(args[1]);
}
catch
{
Console.WriteLine("");
Console.WriteLine(" OPTION = 0 to get the standard rule for handling:");
Console.WriteLine(" Integral ( A <= x < +oo ) exp(-x) f(x) dx");
Console.WriteLine("");
Console.WriteLine(" OPTION = 1 to get the modified rule for handling:");
Console.WriteLine(" Integral ( A <= x < +oo ) f(x) dx");
Console.WriteLine("");
Console.WriteLine(" Enter the value of OPTION:");
option = Convert.ToInt32(Console.ReadLine());
}
Console.WriteLine("");
Console.WriteLine(" The requested value of OPTION = " + option + "");
//
// Get the output option or quadrature file root name:
//
try
{
output = args[2];
}
catch
{
Console.WriteLine("");
Console.WriteLine(" Enter OUTPUT (one of C++, F77, F90, MAT");
Console.WriteLine(" or else the \"root name\" of the quadrature files).");
output = Console.ReadLine();
}
Console.WriteLine("");
Console.WriteLine(" OUTPUT option is \"" + output + "\".");
//
// Construct the rule and output it.
//
QuadratureRule.laguerre_handle(order, a, option, output);
//
// Terminate.
//
Console.WriteLine("");
Console.WriteLine("LAGUERRE_RULE_SS:");
Console.WriteLine(" Normal end of execution.");
Console.WriteLine("");
}
