Subversion Repositories slepc-dev

/*

   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

   SLEPc - Scalable Library for Eigenvalue Problem Computations

   Copyright (c) 2002-2010, Universidad Politecnica de Valencia, Spain

   This file is part of SLEPc.

   SLEPc is free software: you can redistribute it and/or modify it under  the

   terms of version 3 of the GNU Lesser General Public License as published by

   the Free Software Foundation.

   SLEPc  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 SLEPc. If not, see <http://www.gnu.org/licenses/>.

   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

*/

static char help[] = "Solves a generalized eigensystem Ax=kBx with matrices loaded from a file.\n"

  "This example works for both real and complex numbers.\n\n"

  "The command line options are:\n"

  "  -f1 <filename>, where <filename> = matrix (A) file in PETSc binary form.\n"

  "  -f2 <filename>, where <filename> = matrix (B) file in PETSc binary form.\n\n";

#include "slepceps.h"

#undef __FUNCT__

#define __FUNCT__ "main"

int main( int argc, char **argv )

{

  Mat            A,B;             /* matrices */

  EPS            eps;             /* eigenproblem solver context */

  const EPSType  type;

  PetscReal      error, tol, re, im;

  PetscScalar    kr, ki;

  PetscErrorCode ierr;

  PetscInt       nev, maxit, i, its, lits, nconv;

  char           filename[256];

  PetscViewer    viewer;

  PetscTruth     flg;

  SlepcInitialize(&argc,&argv,(char*)0,help);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        Load the matrices that define the eigensystem, Ax=kBx

     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

  ierr = PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized eigenproblem stored in file.\n\n");CHKERRQ(ierr);

  ierr = PetscOptionsGetString(PETSC_NULL,"-f1",filename,256,&flg);CHKERRQ(ierr);

  if (!flg) {

    SETERRQ(PETSC_COMM_WORLD,1,"Must indicate a file name for matrix A with the -f1 option.");

  }

#if defined(PETSC_USE_COMPLEX)

  ierr = PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrices from binary files...\n");CHKERRQ(ierr);

#else

  ierr = PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrices from binary files...\n");CHKERRQ(ierr);

#endif

  ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);CHKERRQ(ierr);

  ierr = MatLoad(viewer,MATAIJ,&A);CHKERRQ(ierr);

  ierr = PetscViewerDestroy(viewer);CHKERRQ(ierr);

  ierr = PetscOptionsGetString(PETSC_NULL,"-f2",filename,256,&flg);CHKERRQ(ierr);

  if (!flg) {

    SETERRQ(PETSC_COMM_WORLD,1,"Must indicate a file name for matrix B with the -f2 option.");

  }

  ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);CHKERRQ(ierr);

  ierr = MatLoad(viewer,MATAIJ,&B);CHKERRQ(ierr);

  ierr = PetscViewerDestroy(viewer);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

                Create the eigensolver and set various options

     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

  /*

     Create eigensolver context

  */

  ierr = EPSCreate(PETSC_COMM_WORLD,&eps);CHKERRQ(ierr);

  /*

     Set operators. In this case, it is a generalized eigenvalue problem

  */

  ierr = EPSSetOperators(eps,A,B);CHKERRQ(ierr);

  /*

     Set solver parameters at runtime

  */

  ierr = EPSSetFromOptions(eps);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

                      Solve the eigensystem

     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

  ierr = EPSSolve(eps);CHKERRQ(ierr);

  /*

     Optional: Get some information from the solver and display it

  */

  ierr = EPSGetIterationNumber(eps, &its);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD," Number of iterations of the method: %d\n",its);CHKERRQ(ierr);

  ierr = EPSGetOperationCounters(eps,PETSC_NULL,PETSC_NULL,&lits);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD," Number of linear iterations of the method: %d\n",lits);CHKERRQ(ierr);

  ierr = EPSGetType(eps,&type);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);CHKERRQ(ierr);

  ierr = EPSGetDimensions(eps,&nev,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %d\n",nev);CHKERRQ(ierr);

  ierr = EPSGetTolerances(eps,&tol,&maxit);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD," Stopping condition: tol=%.4g, maxit=%d\n",tol,maxit);CHKERRQ(ierr);

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

                    Display solution and clean up

     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

  /*

     Get number of converged eigenpairs

  */

  ierr = EPSGetConverged(eps,&nconv);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD," Number of converged approximate eigenpairs: %d\n\n",nconv);CHKERRQ(ierr);

  if (nconv>0) {

    /*

       Display eigenvalues and relative errors

    */

    ierr = PetscPrintf(PETSC_COMM_WORLD,

         "           k             ||Ax-kBx||/||kx||\n"

         "  --------------------- ------------------\n" );CHKERRQ(ierr);

    for( i=0; i<nconv; i++ ) {

      /*

         Get converged eigenpairs: i-th eigenvalue is stored in kr (real part) and

         ki (imaginary part)

      */

      ierr = EPSGetEigenpair(eps,i,&kr,&ki,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);

      /*

         Compute the relative error associated to each eigenpair

      */

      ierr = EPSComputeRelativeError(eps,i,&error);CHKERRQ(ierr);

#if defined(PETSC_USE_COMPLEX)

      re = PetscRealPart(kr);

      im = PetscImaginaryPart(kr);

#else

      re = kr;

      im = ki;

#endif

      if( im != 0.0 ) {

        ierr = PetscPrintf(PETSC_COMM_WORLD," % 6f %+6f i",re,im);CHKERRQ(ierr);

      } else {

        ierr = PetscPrintf(PETSC_COMM_WORLD,"       % 6f      ",re); CHKERRQ(ierr);

      }

      ierr = PetscPrintf(PETSC_COMM_WORLD," % 12g\n",error);CHKERRQ(ierr);

    }

    ierr = PetscPrintf(PETSC_COMM_WORLD,"\n" );CHKERRQ(ierr);

  }

  /*

     Free work space

  */

  ierr = EPSDestroy(eps);CHKERRQ(ierr);

  ierr = MatDestroy(A);CHKERRQ(ierr);

  ierr = MatDestroy(B);CHKERRQ(ierr);

  ierr = SlepcFinalize();CHKERRQ(ierr);

  return 0;

}