Use LOBPCG with Epetra and Ifpack preconditioner.
Use LOBPCG with Epetra and Ifpack preconditioner.This example computes the eigenvalues of largest magnitude of an generalized eigenvalue problem, using Anasazi's implementation of the LOBPCG method, with Epetra linear algebra. It preconditions LOBPCG with an Ifpack incomplete Cholesky preconditioner.
#include "Epetra_CrsMatrix.h"
#include "Epetra_InvOperator.h"
#include "Teuchos_CommandLineProcessor.hpp"
#include "Ifpack.h"
#ifdef HAVE_MPI
#include "Epetra_MpiComm.h"
#include <mpi.h>
#else
#include "Epetra_SerialComm.h"
#endif
#include "Epetra_Map.h"
#include "ModeLaplace2DQ2.h"
int
main (int argc, char *argv[])
{
using Teuchos::RCP;
using Teuchos::rcp;
using std::endl;
#ifdef HAVE_MPI
MPI_Init (&argc, &argv);
#endif
#ifdef HAVE_MPI
Epetra_MpiComm Comm (MPI_COMM_WORLD);
#else
Epetra_SerialComm Comm;
#endif
int nev = 10;
int blockSize = 5;
int maxIters = 500;
double tol = 1.0e-8;
int numElements = 10;
bool verbose = true;
std::string which ("SM");
bool usePrec = true;
double prec_dropTol = 1e-4;
int prec_lofill = 0;
Teuchos::CommandLineProcessor cmdp(false,true);
cmdp.setOption("nev",&nev,"Number of eigenpairs to compted.");
cmdp.setOption("maxIters",&maxIters,"Maximum number of iterations.");
cmdp.setOption("blockSize",&blockSize,"Block size.");
cmdp.setOption("tol",&tol,"Relative convergence tolerance.");
cmdp.setOption("numElements",&numElements,"Number of elements in the discretization.");
cmdp.setOption("verbose","quiet",&verbose,"Print messages and results.");
cmdp.setOption("sort",&which,"Targetted eigenvalues (SM or LM).");
cmdp.setOption("usePrec","noPrec",&usePrec,"Use Ifpack for preconditioning.");
cmdp.setOption("prec_dropTol",&prec_dropTol,"Preconditioner: drop tolerance.");
cmdp.setOption("prec_lofill",&prec_lofill,"Preconditioner: level of fill.");
if (cmdp.parse(argc,argv) != Teuchos::CommandLineProcessor::PARSE_SUCCESSFUL) {
#ifdef HAVE_MPI
MPI_Finalize ();
#endif
return -1;
}
if (verbose) {
}
BasicOutputManager<double> printer (verbosity);
printer.stream(Errors) << Anasazi_Version() << endl << endl;
typedef Epetra_MultiVector MV;
typedef Epetra_Operator OP;
typedef MultiVecTraits<double, Epetra_MultiVector> MVT;
printer.stream(Errors) << "Generating problem matrices..." << std::flush;
const int space_dim = 2;
std::vector<double> brick_dim (space_dim);
brick_dim[0] = 1.0;
brick_dim[1] = 1.0;
std::vector<int> elements (space_dim);
elements[0] = numElements;
elements[1] = numElements;
RCP<ModalProblem> testCase =
rcp( new ModeLaplace2DQ2(Comm, brick_dim[0], elements[0], brick_dim[1], elements[1]) );
RCP<Epetra_CrsMatrix> K = rcp( const_cast<Epetra_CrsMatrix *>(testCase->getStiffness()), false );
RCP<Epetra_CrsMatrix> M = rcp( const_cast<Epetra_CrsMatrix *>(testCase->getMass()), false );
printer.stream(Errors) << " done." << endl;
RCP<Ifpack_Preconditioner> prec;
RCP<Epetra_Operator> PrecOp;
if (usePrec) {
printer.stream(Errors) << "Constructing Incomplete Cholesky preconditioner..." << std::flush;
Ifpack precFactory;
std::string precType = "IC stand-alone";
int overlapLevel = 0;
prec = rcp (precFactory.Create (precType, K.get (), overlapLevel));
Teuchos::ParameterList precParams;
precParams.set("fact: drop tolerance",prec_dropTol);
precParams.set("fact: level-of-fill",prec_lofill);
IFPACK_CHK_ERR(prec->SetParameters(precParams));
IFPACK_CHK_ERR(prec->Initialize());
IFPACK_CHK_ERR(prec->Compute());
printer.stream(Errors) << " done." << endl;
PrecOp = rcp (new Epetra_InvOperator (&*prec));
}
RCP<Epetra_MultiVector> ivec
= rcp (new Epetra_MultiVector (K->OperatorDomainMap (), blockSize));
ivec->Random ();
RCP<BasicEigenproblem<double, MV, OP> > MyProblem =
rcp (new BasicEigenproblem<double, MV, OP> (K, M, ivec));
MyProblem->setHermitian (true);
if (usePrec) {
MyProblem->setPrec (PrecOp);
}
MyProblem->setNEV (nev);
const bool success = MyProblem->setProblem ();
if (! success) {
printer.print (Errors, "Anasazi::BasicEigenproblem::setProblem() reported an error.\n");
#ifdef HAVE_MPI
MPI_Finalize ();
#endif
return -1;
}
Teuchos::ParameterList MyPL;
MyPL.set( "Verbosity", verbosity );
MyPL.set( "Which", which );
MyPL.set( "Block Size", blockSize );
MyPL.set( "Maximum Iterations", maxIters );
MyPL.set( "Convergence Tolerance", tol );
MyPL.set( "Full Ortho", true );
MyPL.set( "Use Locking", true );
LOBPCGSolMgr<double, MV, OP> MySolverMan(MyProblem, MyPL);
printer.stream(Errors) << "Solving eigenvalue problem..." << endl;
if (usePrec) {
printer.stream(FinalSummary) << *prec << endl;
}
Eigensolution<double,MV> sol = MyProblem->getSolution();
std::vector<Value<double> > evals = sol.Evals;
RCP<MV> evecs = sol.Evecs;
std::vector<double> normR(sol.numVecs);
if (sol.numVecs > 0) {
Teuchos::SerialDenseMatrix<int,double> T(sol.numVecs, sol.numVecs);
Epetra_MultiVector Kvec( K->OperatorDomainMap(), evecs->NumVectors() );
Epetra_MultiVector Mvec( M->OperatorDomainMap(), evecs->NumVectors() );
T.putScalar(0.0);
for (int i=0; i<sol.numVecs; i++) {
T(i,i) = evals[i].realpart;
}
K->Apply( *evecs, Kvec );
M->Apply( *evecs, Mvec );
MVT::MvTimesMatAddMv( -1.0, Mvec, T, 1.0, Kvec );
MVT::MvNorm( Kvec, normR );
}
std::ostringstream os;
os.setf (std::ios_base::right, std::ios_base::adjustfield);
os << "Solver manager returned "
<< (returnCode == Converged ? "converged." : "unconverged.") << endl;
os << endl;
os << "------------------------------------------------------" << endl;
os << std::setw(16) << "Eigenvalue"
<< std::setw(18) << "Direct Residual"
<< endl;
os << "------------------------------------------------------" << endl;
for (int i=0; i<sol.numVecs; ++i) {
os << std::setw(16) << evals[i].realpart
<< std::setw(18) << normR[i]/evals[i].realpart
<< endl;
}
os << "------------------------------------------------------" << endl;
printer.print (Errors, os.str ());
#ifdef HAVE_MPI
MPI_Finalize();
#endif
return 0;
}
Basic implementation of the Anasazi::Eigenproblem class.
Basic output manager for sending information of select verbosity levels to the appropriate output str...
Declarations of Anasazi multi-vector and operator classes using Epetra_MultiVector and Epetra_Operato...
The Anasazi::LOBPCGSolMgr provides a powerful solver manager for the LOBPCG eigensolver.
Namespace Anasazi contains the classes, structs, enums and utilities used by the Anasazi package.
ReturnType
Enumerated type used to pass back information from a solver manager.