doc/html/GCRODR_2PrecGCRODREpetraExFile_8cpp-example.html

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//                 Belos: Block Linear Solvers Package

//                  Copyright 2004 Sandia Corporation

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// This driver reads a problem from a file, which can be in Harwell-Boeing (*.hb),

// Matrix Market (*.mtx), or triplet format (*.triU, *.triS).  The right-hand side

// from the problem, if it exists, will be used instead of multiple random

// right-hand-sides.  The initial guesses are all set to zero.  An ILU preconditioner

// is constructed using the Ifpack factory.

//

#include "BelosConfigDefs.hpp"

#include "BelosLinearProblem.hpp"

#include "BelosEpetraAdapter.hpp"

#include "BelosGCRODRSolMgr.hpp"

#include "BelosEpetraUtils.h"

#include "Ifpack_IlukGraph.h"

#include "Ifpack_CrsRiluk.h"

#include "Epetra_Map.h"

#ifdef EPETRA_MPI

  #include "Epetra_MpiComm.h"

#else

  #include "Epetra_SerialComm.h"

#endif

#include "Epetra_CrsMatrix.h"

#include "Teuchos_CommandLineProcessor.hpp"

#include "Teuchos_ParameterList.hpp"

#include "Teuchos_StandardCatchMacros.hpp"


int main(int argc, char *argv[]) {

  //

  int MyPID = 0;

#ifdef EPETRA_MPI

  // Initialize MPI

  MPI_Init(&argc,&argv);

  Epetra_MpiComm Comm(MPI_COMM_WORLD);

  MyPID = Comm.MyPID();

#else

  Epetra_SerialComm Comm;

#endif

  //

  typedef double                            ST;

  typedef Teuchos::ScalarTraits<ST>        SCT;

  typedef SCT::magnitudeType                MT;

  typedef Epetra_MultiVector                MV;

  typedef Epetra_Operator                   OP;

  typedef Belos::MultiVecTraits<ST,MV>     MVT;

  typedef Belos::OperatorTraits<ST,MV,OP>  OPT;


  using Teuchos::ParameterList;

  using Teuchos::RCP;

  using Teuchos::rcp;


bool verbose = false;

bool success = true;

try {

bool proc_verbose = false;

  bool debug = false;

  bool leftprec = true;      // left preconditioning or right.

  int frequency = -1;        // frequency of status test output.

  int numrhs = 1;            // number of right-hand sides to solve for

  int maxiters = -1;         // maximum number of iterations allowed per linear system

  int maxsubspace = 250;     // maximum number of blocks the solver can use for the subspace

  int recycle = 50;          // maximum size of recycle space

  int maxrestarts = 15;      // maximum number of restarts allowed

  std::string filename("sherman5.hb");

  std::string ortho("IMGS");

  MT tol = 1.0e-10;          // relative residual tolerance


  Teuchos::CommandLineProcessor cmdp(false,true);

  cmdp.setOption("verbose","quiet",&verbose,"Print messages and results.");

  cmdp.setOption("debug","nondebug",&debug, "Print debugging information from solver.");

  cmdp.setOption("left-prec","right-prec",&leftprec,"Left preconditioning or right.");

  cmdp.setOption("frequency",&frequency,"Solvers frequency for printing residuals (#iters).");

  cmdp.setOption("filename",&filename,"Filename for test matrix.  Acceptable file extensions: *.hb,*.mtx,*.triU,*.triS");

  cmdp.setOption("tol",&tol,"Relative residual tolerance used by GMRES solver.");

  cmdp.setOption("num-rhs",&numrhs,"Number of right-hand sides to be solved for.");

  cmdp.setOption("max-iters",&maxiters,"Maximum number of iterations per linear system (-1 = adapted to problem/block size).");

  cmdp.setOption("max-subspace",&maxsubspace,"Maximum number of blocks the solver can use for the subspace.");

  cmdp.setOption("recycle",&recycle,"Number of vectors in recycle space.");

  cmdp.setOption("max-cycles",&maxrestarts,"Maximum number of cycles allowed for GCRO-DR solver.");

  cmdp.setOption("ortho-type",&ortho,"Orthogonalization type. Must be one of DGKS, ICGS, IMGS.");

  if (cmdp.parse(argc,argv) != Teuchos::CommandLineProcessor::PARSE_SUCCESSFUL) {

    return -1;

  }

  if (!verbose)

    frequency = -1;  // reset frequency if test is not verbose


  //

  // *************Get the problem*********************

  //

  RCP<Epetra_CrsMatrix> A;

  RCP<Epetra_MultiVector> B, X;

  int return_val =Belos::Util::createEpetraProblem(filename,NULL,&A,NULL,NULL,&MyPID);

  const Epetra_Map &Map = A->RowMap();

  if(return_val != 0) return return_val;

  proc_verbose = verbose && (MyPID==0); /* Only print on zero processor */

  X = rcp( new Epetra_MultiVector( Map, numrhs ) );

  B = rcp( new Epetra_MultiVector( Map, numrhs ) );

  X->Random();

  OPT::Apply( *A, *X, *B );

  X->PutScalar( 0.0 );

  //

  // ************Construct preconditioner*************

  //

  if (proc_verbose) std::cout << std::endl << std::endl;

  if (proc_verbose) std::cout << "Constructing ILU preconditioner" << std::endl;

  int Lfill = 2;

  if (proc_verbose) std::cout << "Using Lfill = " << Lfill << std::endl;

  int Overlap = 2;

  if (proc_verbose) std::cout << "Using Level Overlap = " << Overlap << std::endl;

  double Athresh = 0.0;

  if (proc_verbose) std::cout << "Using Absolute Threshold Value of " << Athresh << std::endl;

  double Rthresh = 1.0;

  if (proc_verbose) std::cout << "Using Relative Threshold Value of " << Rthresh << std::endl;

  //

  Teuchos::RCP<Ifpack_IlukGraph> ilukGraph;

  Teuchos::RCP<Ifpack_CrsRiluk> ilukFactors;

  //

  ilukGraph = Teuchos::rcp(new Ifpack_IlukGraph(A->Graph(), Lfill, Overlap));

  int info = ilukGraph->ConstructFilledGraph();

  assert( info == 0 );

  ilukFactors = Teuchos::rcp(new Ifpack_CrsRiluk(*ilukGraph));

  int initerr = ilukFactors->InitValues(*A);

  if (initerr != 0) std::cout << "InitValues error = " << initerr;

  info = ilukFactors->Factor();

  assert( info == 0 );

  bool transA = false;

  double Cond_Est;

  ilukFactors->Condest(transA, Cond_Est);

  if (proc_verbose) {

    std::cout << "Condition number estimate for this preconditoner = " << Cond_Est << std::endl;

    std::cout << std::endl;

  }


  // Create the Belos preconditioned operator from the Ifpack preconditioner.

  // NOTE:  This is necessary because Belos expects an operator to apply the

  //        preconditioner with Apply() NOT ApplyInverse().

  RCP<Belos::EpetraPrecOp> belosPrec = rcp( new Belos::EpetraPrecOp( ilukFactors ) );


  //

  // ********Other information used by block solver***********

  // *****************(can be user specified)******************

  //

  const int NumGlobalElements = B->GlobalLength();

  if (maxiters == -1)

    maxiters = NumGlobalElements - 1; // maximum number of iterations to run

  //

  ParameterList belosList;

  belosList.set( "Num Blocks", maxsubspace );            // Maximum number of blocks in Krylov factorization

  belosList.set( "Maximum Iterations", maxiters );       // Maximum number of iterations allowed

  belosList.set( "Maximum Restarts", maxrestarts );      // Maximum number of restarts allowed

  belosList.set( "Convergence Tolerance", tol );         // Relative convergence tolerance requested

  belosList.set( "Num Recycled Blocks", recycle );       // Number of vectors in recycle space

  belosList.set( "Orthogonalization", ortho );           // Orthogonalization type

  if (numrhs > 1) {

    belosList.set( "Show Maximum Residual Norm Only", true );  // Show only the maximum residual norm

  }

  int verbosity = Belos::Errors + Belos::Warnings;

  if (verbose) {

    verbosity += Belos::TimingDetails + Belos::StatusTestDetails;

    if (frequency > 0)

      belosList.set( "Output Frequency", frequency );

  }

  if (debug) {

    verbosity += Belos::Debug;

  }

  belosList.set( "Verbosity", verbosity );

  //

  // *******Construct a preconditioned linear problem********

  //

  RCP<Belos::LinearProblem<double,MV,OP> > problem

    = rcp( new Belos::LinearProblem<double,MV,OP>( A, X, B ) );

  if (leftprec) {

    problem->setLeftPrec( belosPrec );

  }

  else {

    problem->setRightPrec( belosPrec );

  }

  bool set = problem->setProblem();

  if (set == false) {

    if (proc_verbose)

      std::cout << std::endl << "ERROR:  Belos::LinearProblem failed to set up correctly!" << std::endl;

    return -1;

  }


  // Create an iterative solver manager.

  RCP< Belos::SolverManager<double,MV,OP> > solver

    = rcp( new Belos::GCRODRSolMgr<double,MV,OP>(problem, rcp(&belosList,false)));


  //

  // *******************************************************************

  // *************Start the block Gmres iteration*************************

  // *******************************************************************

  //

  if (proc_verbose) {

    std::cout << std::endl << std::endl;

    std::cout << "Dimension of matrix: " << NumGlobalElements << std::endl;

    std::cout << "Number of right-hand sides: " << numrhs << std::endl;

    std::cout << "Number of restarts allowed: " << maxrestarts << std::endl;

    std::cout << "Max number of Gmres iterations per restart cycle: " << maxiters << std::endl;

    std::cout << "Relative residual tolerance: " << tol << std::endl;

    std::cout << std::endl;

  }

  //

  // Perform solve

  //

  Belos::ReturnType ret = solver->solve();

  //

  // Compute actual residuals.

  //

  bool badRes = false;

  std::vector<double> actual_resids( numrhs );

  std::vector<double> rhs_norm( numrhs );

  Epetra_MultiVector resid(Map, numrhs);

  OPT::Apply( *A, *X, resid );

  MVT::MvAddMv( -1.0, resid, 1.0, *B, resid );

  MVT::MvNorm( resid, actual_resids );

  MVT::MvNorm( *B, rhs_norm );

  if (proc_verbose) {

    std::cout<< "---------- Actual Residuals (normalized) ----------"<<std::endl<<std::endl;

    for ( int i=0; i<numrhs; i++) {

      double actRes = actual_resids[i]/rhs_norm[i];

      std::cout<<"Problem "<<i<<" : \t"<< actRes <<std::endl;

      if (actRes > tol) badRes = true;

    }

  }


if (ret!=Belos::Converged || badRes) {

  success = false;

  if (proc_verbose)

    std::cout << std::endl << "ERROR:  Belos did not converge!" << std::endl;

} else {

  success = true;

  if (proc_verbose)

    std::cout << std::endl << "SUCCESS:  Belos converged!" << std::endl;

}

}

TEUCHOS_STANDARD_CATCH_STATEMENTS(verbose, std::cerr, success);


#ifdef EPETRA_MPI

MPI_Finalize();

#endif


return success ? EXIT_SUCCESS : EXIT_FAILURE;

}