This page describes how to write the main file for using NOX's Epetra implementation of the Group and Vector.
This example can be found in Trilinos/packages/nox/test/epetra/1Dfem/1Dfem.C
Begin by including the NOX library header files and any other headers needed by your application:
#include "NOX.H"
#include "NOX_Epetra.H"
#ifdef HAVE_MPI
#include "Epetra_MpiComm.h"
#else
#include "Epetra_SerialComm.h"
#endif
#include "Epetra_Map.h"
#include "Epetra_Vector.h"
#include "Epetra_RowMatrix.h"
#include "Epetra_CrsMatrix.h"
#include "Epetra_Map.h"
#include "Epetra_LinearProblem.h"
#include "1DfemInterface.H"
#include "1DfemPrePostOperator.H"
#include "Teuchos_ParameterList.hpp"
For convenience define the following:
Begin by initializing MPI (if building a parallel version) and create the Epetra communicator for MPI. In this case autoconf defines the flag HAVE_MPI if we are building a parallel version.
int main(int argc, char *argv[])
{
#ifdef HAVE_MPI
MPI_Init(&argc,&argv);
#endif
#ifdef HAVE_MPI
#else
#endif
Setup some initial values.
int MyPID = Comm.
MyPID();
bool verbose = false;
if (argc > 1)
if (argv[1][0]=='-' && argv[1][1]=='v')
verbose = true;
int NumGlobalElements = 0;
if ((argc > 2) && (verbose))
NumGlobalElements = atoi(argv[2]) + 1;
else if ((argc > 1) && (!verbose))
NumGlobalElements = atoi(argv[1]) + 1;
else
NumGlobalElements = 101;
if (NumGlobalElements < NumProc) {
cout << "numGlobalBlocks = " << NumGlobalElements
<< " cannot be < number of processors = " << NumProc << std::endl;
cout << "Test failed!" << std::endl;
throw "NOX Error";
}
Create your object that derives from NOX::Epetra::Interface::Required so that nox has access to the set of nonlinear equations to solve.
Teuchos::RCP<Interface> interface =
Teuchos::rcp(new Interface(NumGlobalElements, Comm));
Grab the initial guess vector and initialize it and the interface object.
Teuchos::RCP<Epetra_Vector> soln = interface->getSolution();
Teuchos::RCP<NOX::Epetra::Vector> noxSoln =
interface->setPDEfactor(1000.0);
soln->PutScalar(1.0);
Implementation of NOX::Abstract::Vector for Epetra vectors.
Definition: NOX_Epetra_Vector.H:72
@ CreateView
Keeps a pointer to and uses the actual Epetra_Vector passed in.
Definition: NOX_Epetra_Vector.H:79
Create a parameter list and choose the options for the NOX solver. Note that the linear solver parameters in teh "Linear Solver" sublist are dependent upon what NOX::Epetra::LinearSystem object you are using. Currently NOX only comes with one concrete linear system implementation: NOX::EpetraLinearSystemAztecOO.
Teuchos::RCP<Teuchos::ParameterList> nlParamsPtr =
Teuchos::rcp(new Teuchos::ParameterList);
Teuchos::ParameterList& nlParams = *(nlParamsPtr.get());
nlParams.set("Nonlinear Solver", "Line Search Based");
Teuchos::ParameterList& printParams = nlParams.sublist("Printing");
printParams.set("MyPID", MyPID);
printParams.set("Output Precision", 3);
printParams.set("Output Processor", 0);
if (verbose)
printParams.set("Output Information",
else
Teuchos::ParameterList& searchParams = nlParams.sublist("Line Search");
searchParams.set("Method", "Full Step");
Teuchos::ParameterList& dirParams = nlParams.sublist("Direction");
dirParams.set("Method", "Newton");
Teuchos::ParameterList& newtonParams = dirParams.sublist("Newton");
newtonParams.set("Forcing Term Method", "Constant");
Teuchos::ParameterList& lsParams = newtonParams.sublist("Linear Solver");
lsParams.set("Aztec Solver", "GMRES");
lsParams.set("Max Iterations", 800);
lsParams.set("Tolerance", 1e-4);
lsParams.set("Preconditioner", "New Ifpack");
lsParams.set("Preconditioner Reuse Policy", "Reuse");
lsParams.set("Max Age Of Prec", 5);
@ InnerIteration
2^2
Definition: NOX_Utils.H:152
@ OuterIteration
2^1
Definition: NOX_Utils.H:150
@ LinearSolverDetails
2^6
Definition: NOX_Utils.H:160
@ Warning
2^0
Definition: NOX_Utils.H:148
@ Parameters
2^3
Definition: NOX_Utils.H:154
@ Error
Errors are always printed.
Definition: NOX_Utils.H:146
@ TestDetails
2^7
Definition: NOX_Utils.H:162
@ Debug
2^12
Definition: NOX_Utils.H:170
@ OuterIterationStatusTest
2^5
Definition: NOX_Utils.H:158
@ Details
2^4
Definition: NOX_Utils.H:156
Optionally the user can define methods that will be called before and after each nonlineaer iteration and before and after each nonlinear solve. This is done by creating an object derived from NOX::Abstract::PrePostOperator.
Teuchos::RCP<NOX::Abstract::PrePostOperator> ppo =
Teuchos::rcp(new UserPrePostOperator(printing));
nlParams.sublist("Solver Options").set("User Defined Pre/Post Operator",
ppo);
Set the status test check option.
nlParams.sublist("Solver Options").
@ Complete
Evaluate every test and subtest.
Definition: NOX_StatusTest_Generic.H:84
Create a Jacobian-Free Newton-Krylov method by using a NOX::Epetra::MatrixFree operator for the Jacobian.
Teuchos::RCP<NOX::Epetra::MatrixFree> MF =
*noxSoln));
Concrete implementation for creating an Epetra_Operator Jacobian based on the Matrix-Free Newton-Kryl...
Definition: NOX_Epetra_MatrixFree.H:101
Create a Finite Difference operator to estimate the Jacobian matrix for preconditioning.
Teuchos::RCP<NOX::Epetra::FiniteDifference> FD =
*soln));
Concrete implementation for creating an Epetra_RowMatrix Jacobian via finite differencing of the resi...
Definition: NOX_Epetra_FiniteDifference.H:112
Create a linear system derived from NOX::Epetra::LinearSystem. NOX comes with a concrete implementation of the linear system class that uses AztecOO as the linear solver called NOX::Epetra::LinearSystemAztecOO. In this case we will use the constructor that specifies the Jacobian operator and a preconditioner matrix to be used with an internally constructed AztecOO preconditioner.
Teuchos::RCP<NOX::Epetra::Interface::Jacobian> iJac = MF;
Teuchos::RCP<NOX::Epetra::Interface::Preconditioner> iPrec = FD;
Teuchos::RCP<NOX::Epetra::LinearSystemAztecOO> linSys =
iJac, MF,
iPrec, FD,
*soln));
Concrete implementation of NOX::Epetra::LinearSolver for AztecOO.
Definition: NOX_Epetra_LinearSystem_AztecOO.H:321
Create the group using the linear system.
Teuchos::RCP<NOX::Epetra::Group> grpPtr =
iReq,
initialGuess,
linSys));
Concrete implementation of NOX::Abstract::Group for Trilinos/Epetra.
Definition: NOX_Epetra_Group.H:90
Create the status tests to determine how to terminate the nonlinear solve.
Teuchos::RCP<NOX::StatusTest::NormF> absresid =
Teuchos::RCP<NOX::StatusTest::NormF> relresid =
Teuchos::RCP<NOX::StatusTest::NormUpdate> update =
Teuchos::RCP<NOX::StatusTest::NormWRMS> wrms =
Teuchos::RCP<NOX::StatusTest::Combo> converged =
converged->addStatusTest(absresid);
converged->addStatusTest(relresid);
converged->addStatusTest(wrms);
converged->addStatusTest(update);
Teuchos::RCP<NOX::StatusTest::MaxIters> maxiters =
Teuchos::RCP<NOX::StatusTest::FiniteValue> fv =
Teuchos::RCP<NOX::StatusTest::Combo> combo =
combo->addStatusTest(fv);
combo->addStatusTest(converged);
combo->addStatusTest(maxiters);
Arbitrary combination of status tests.
Definition: NOX_StatusTest_Combo.H:84
@ OR
Logically "OR" together the results of the tests in this combination.
Definition: NOX_StatusTest_Combo.H:96
@ AND
Logically "AND" together the results of the tests in this combination.
Definition: NOX_StatusTest_Combo.H:94
Failure test based on whether the norm of a vector has a finite value.
Definition: NOX_StatusTest_FiniteValue.H:75
Failure test based on the maximum number of nonlinear solver iterations.
Definition: NOX_StatusTest_MaxIters.H:76
Various convergence tests based on the norm of the residual.
Definition: NOX_StatusTest_NormF.H:119
Various convergence tests based on the norm of the change in the solution vector, ,...
Definition: NOX_StatusTest_NormUpdate.H:128
Convergence test based on the weighted root mean square norm fo the solution update between iteration...
Definition: NOX_StatusTest_NormWRMS.H:154
Create the solver and solve the problem
Teuchos::RCP<NOX::Solver::Generic> solver =
NOX::Solver::buildSolver(grpPtr, combo, nlParamsPtr);
StatusType
Status type.
Definition: NOX_StatusTest_Generic.H:69
Get the underlying solution vector in terms of an Epetra_Vector and do whatever you want with it.
getEpetraVector();
virtual const NOX::Abstract::Vector & getX() const
Return solution vector.
Definition: NOX_Epetra_Group.C:553
Exit simulation.