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// @HEADER
// ***********************************************************************
// 
//                      Didasko Tutorial Package
//                 Copyright (2005) Sandia Corporation
// 
// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
// license for use of this work by or on behalf of the U.S. Government.
// 
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//  
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//  
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA
//
// Questions about Didasko? Contact Marzio Sala (marzio.sala _AT_ gmail.com)
// 
// ***********************************************************************
// @HEADER

#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;
  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
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