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CommandLineProcessor/cxx_main.cpp

This is an example of how to use the Teuchos::CommandLineProcessor class.

// @HEADER
// *****************************************************************************
// Teuchos: Common Tools Package
//
// Copyright 2004 NTESS and the Teuchos contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER
#include "Teuchos_oblackholestream.hpp"
#include "Teuchos_StandardCatchMacros.hpp"
#include "Teuchos_Version.hpp"
// Enum for the speed option
enum ESpeed { SPEED_SLOW=-1, SPEED_MEDIUM=0, SPEED_FAST=+1 };
int main(int argc, char* argv[])
{
Teuchos::GlobalMPISession mpiSession(&argc,&argv);
const int procRank = Teuchos::GlobalMPISession::getRank();
std::ostream &out = ( procRank == 0 ? std::cout : blackhole );
bool success = true;
try {
out << Teuchos::Teuchos_Version() << std::endl << std::endl;
// Creating an empty command line processor looks like:
My_CLP.setDocString(
"This example program demonstrates how to use this Teuchos::CommandLineProcessor class\n"
"to get options from the command-line and print this help messange automatically.\n"
);
/* To set and option, it must be given a name and default value. Additionally,
each option can be given a help std::string. Although it is not necessary, a help
std::string aids a users comprehension of the acceptable command line arguments.
Some examples of setting command line options are:
*/
// Set an integer command line option.
int NumIters = 1550;
My_CLP.setOption("iterations", &NumIters, "Number of iterations");
// Set a long integer command line option
long int MatrixDim = Teuchos::OrdinalTraits<long int>::max();
My_CLP.setOption("long-matrix-dim", &MatrixDim, "Matrix dimension (long)");
long long int MatrixDim2 = Teuchos::OrdinalTraits<long long int>::max();
My_CLP.setOption("long-long-matrix-dim", &MatrixDim2, "Matrix dimension (long long)");
// Set a double-precision command line option.
double Tolerance = 1e-10;
My_CLP.setOption("tolerance", &Tolerance, "Tolerance");
// Set a std::string command line option.
std::string Solver = "GMRES";
My_CLP.setOption("solver", &Solver, "Linear solver");
// Set a boolean command line option.
bool Precondition = true;
My_CLP.setOption("precondition","no-precondition",
&Precondition,"Preconditioning flag");
// Set an enumeration command line option
const int num_speed_values = 3;
const ESpeed speed_opt_values[] = { SPEED_SLOW, SPEED_MEDIUM, SPEED_FAST };
const char* speed_opt_names[] = { "slow", "medium", "fast" };
ESpeed Speed = SPEED_MEDIUM;
My_CLP.setOption(
"speed", &Speed,
num_speed_values, speed_opt_values, speed_opt_names,
"Speed of our solver"
);
/* There are also two methods that control the behavior of the
command line processor. First, for the command line processor to
allow an unrecognized a command line option to be ignored (and
only have a warning printed), use:
*/
My_CLP.recogniseAllOptions(true);
/* Second, by default, if the parser finds a command line option it
doesn't recognize or finds the --help option, it will throw an
std::exception. If you want prevent a command line processor from
throwing an std::exception (which is important in this program since
we don't have an try/catch around this) when it encounters a
unrecognized option or help is printed, use:
*/
My_CLP.throwExceptions(false);
/* We now parse the command line where argc and argv are passed to
the parse method. Note that since we have turned off std::exception
throwing above we had better grab the return argument so that
we can see what happened and act accordingly.
*/
parseReturn= My_CLP.parse( argc, argv );
return 0;
}
return 1; // Error!
}
// Here is where you would use these command line arguments but for this example program
// we will just print the help message with the new values of the command-line arguments.
if (procRank == 0)
out << "\nPrinting help message with new values of command-line arguments ...\n\n";
My_CLP.printHelpMessage(argv[0],out);
// Now we will print the option values
if (procRank == 0) {
out << "\nPrinting user options after parsing ...\n\n";
out << "NumIters = " << NumIters << std::endl;
out << "MatrixDim = " << MatrixDim << std::endl;
out << "MatrixDim2 = " << MatrixDim2 << std::endl;
out << "Tolerance = " << Tolerance << std::endl;
out << "Solver = \"" << Solver << "\"\n";
out << "Precondition = " << Precondition << std::endl;
out << "Speed = " << Speed << std::endl;
}
} // try
TEUCHOS_STANDARD_CATCH_STATEMENTS(true,std::cerr,success);
if(success)
out << "\nEnd Result: TEST PASSED" << std::endl;
return ( success ? 0 : 1 );
}