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//
// Didasko Tutorial Package
// Copyright (2005) Sandia Corporation
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#include "Didasko_ConfigDefs.h"
#ifdef HAVE_MPI
#include "mpi.h"
#endif
#if defined(HAVE_DIDASKO_TEUCHOS)
#include "Teuchos_ParameterList.hpp"
#include "Teuchos_ConfigDefs.hpp"
int main(int argc, char* argv[])
{
#ifdef HAVE_MPI
MPI_Init(&argc,&argv);
#endif
// Creating an empty parameter list looks like:
Teuchos::ParameterList My_List;
// Setting parameters in this list can be easily done:
My_List.set("Max Iters", 1550);
My_List.set("Tolerance", 1e-10);
My_List.set("Solver", "GMRES");
/* The templated ``set'' method should cast the input {\it value} to the
correct data type. However, in the case where the compiler is not casting the input
value to the expected data type, an explicit cast can be used with the ``set'' method:
*/
My_List.set("Tolerance", (float)(1e-10));
/* A hierarchy of parameter lists can be constructed using {\tt Teuchos::ParameterList}. This
means another parameter list is a valid {\it value} in any parameter list. To create a sublist
in a parameter list and obtain a reference to it:
*/
Teuchos::ParameterList& Prec_List = My_List.sublist("Preconditioner");
// Now this parameter list can be filled with values:
Prec_List.set("Type", "ILU");
Prec_List.set("Drop Tolerance", 1e-3);
// The parameter list can be queried about the existance of a parameter, sublist, or type:
// Has a solver been chosen?
bool solver_defined, prec_defined, tol_double, dtol_double;
solver_defined = My_List.isParameter("Solver");
// Has a preconditioner been chosen?
prec_defined = My_List.isSublist("Preconditioner");
// Has a tolerance been chosen and is it a double-precision number?
tol_double = My_List.INVALID_TEMPLATE_QUALIFIER isType<double>("Tolerance");
// Has a drop tolerance been chosen and is it a double-precision number?
dtol_double = Teuchos::isParameterType<double>(Prec_List, "Drop Tolerance");
/* The last two methods for checking the parameter type are equivalent.
There is some question as to whether the syntax of the first type-checking
method is acceptable to older compilers. Thus, the second type-checking method
is offered as a portable alternative.
*/
// Parameters can be retrieved from the parameter list in quite a few ways:
// Get method that creates and sets the parameter if it doesn't exist.
int its;
its = My_List.get("Max Iters", 1200);
// Get method that retrieves a parameter of a particular type.
float tol = My_List.INVALID_TEMPLATE_QUALIFIER get<float>("Tolerance");
/* In the above example, the first ``get'' method is a safe way of
obtaining a parameter when its existence is indefinite but required.
The second ``get'' method should be used when the existense of the parameter
is definite. This method will throw an exception if the parameter doesn't exist.
The safest way to use the second ``get'' method
is in a try/catch block:
*/
try {
tol = My_List.INVALID_TEMPLATE_QUALIFIER get<float>("Tolerance");
}
catch (std::exception& e) {
tol = 1e-6;
}
/* The second ``get'' method uses a syntax that may not be
acceptable to older compilers. Optionally, there is another portable templated
``get'' function that can be used in the place of the second ``get'' method:
*/
try {
tol = Teuchos::getParameter<float>(My_List, "Tolerance");
}
catch (std::exception& e) {
tol = 1e-6;
}
// A parameter list can be sent to the output stream:
cout<< My_List << endl;
/* It is important to note that mispelled parameters
(with additional space characters, capitalizations, etc.) may be ignored.
Therefore, it is important to be aware that a given parameter has not been used.
Unused parameters can be printed with method:
*/
My_List.unused( cout );
#ifdef HAVE_MPI
MPI_Finalize();
#endif
return 0;
}
#else
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
#ifdef HAVE_MPI
MPI_Init(&argc,&argv);
#endif
puts("Please configure Didasko with:\n"
"--enable-teuchos");
#ifdef HAVE_MPI
MPI_Finalize();
#endif
return 0;
}
#endif