Subversion Repositories slepc-dev

/*

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

   SLEPc - Scalable Library for Eigenvalue Problem Computations

   Copyright (c) 2002-2011, Universitat 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[] = "Quadratic eigenproblem for testing the QEP object.\n\n"

  "The command line options are:\n"

  "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"

  "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

#include <slepcqep.h>

#undef __FUNCT__

#define __FUNCT__ "main"

int main(int argc,char **argv)

{

  Mat            M,C,K;           /* problem matrices */

  QEP            qep;             /* quadratic eigenproblem solver context */

  const QEPType  type;

  PetscReal      tol;

  PetscInt       N,n=10,m,Istart,Iend,II,nev,maxit,i,j;

  PetscBool      flag;

  PetscErrorCode ierr;

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

  ierr = PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscOptionsGetInt(PETSC_NULL,"-m",&m,&flag);CHKERRQ(ierr);

  if(!flag) m=n;

  N = n*m;

  ierr = PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%D (%Dx%D grid)\n\n",N,n,m);CHKERRQ(ierr);

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

     Compute the matrices that define the eigensystem, (k^2*K+k*X+M)x=0

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

  /* K is the 2-D Laplacian */

  ierr = MatCreate(PETSC_COMM_WORLD,&K);CHKERRQ(ierr);

  ierr = MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N);CHKERRQ(ierr);

  ierr = MatSetFromOptions(K);CHKERRQ(ierr);

  ierr = MatGetOwnershipRange(K,&Istart,&Iend);CHKERRQ(ierr);

  for (II=Istart;II<Iend;II++) {

    i = II/n; j = II-i*n;  

    if(i>0) { ierr = MatSetValue(K,II,II-n,-1.0,INSERT_VALUES);CHKERRQ(ierr); }

    if(i<m-1) { ierr = MatSetValue(K,II,II+n,-1.0,INSERT_VALUES);CHKERRQ(ierr); }

    if(j>0) { ierr = MatSetValue(K,II,II-1,-1.0,INSERT_VALUES);CHKERRQ(ierr); }

    if(j<n-1) { ierr = MatSetValue(K,II,II+1,-1.0,INSERT_VALUES);CHKERRQ(ierr); }

    ierr = MatSetValue(K,II,II,4.0,INSERT_VALUES);CHKERRQ(ierr);

  }

  ierr = MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  ierr = MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  /* C is the zero matrix */

  ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);

  ierr = MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N);CHKERRQ(ierr);

  ierr = MatSetFromOptions(C);CHKERRQ(ierr);

  ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  /* M is the identity matrix */

  ierr = MatCreate(PETSC_COMM_WORLD,&M);CHKERRQ(ierr);

  ierr = MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N);CHKERRQ(ierr);

  ierr = MatSetFromOptions(M);CHKERRQ(ierr);

  ierr = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  ierr = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

  ierr = MatShift(M,1.0);CHKERRQ(ierr);

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

                Create the eigensolver and set various options

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

  /*

     Create eigensolver context

  */

  ierr = QEPCreate(PETSC_COMM_WORLD,&qep);CHKERRQ(ierr);

  /*

     Set matrices and problem type

  */

  ierr = QEPSetOperators(qep,M,C,K);CHKERRQ(ierr);

  ierr = QEPSetProblemType(qep,QEP_GENERAL);CHKERRQ(ierr);

  /*

     Set solver parameters at runtime

  */

  ierr = QEPSetFromOptions(qep);CHKERRQ(ierr);

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

                      Solve the eigensystem

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

  ierr = QEPSolve(qep);CHKERRQ(ierr);

  /*

     Optional: Get some information from the solver and display it

  */

  ierr = QEPGetType(qep,&type);CHKERRQ(ierr);

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

  ierr = QEPGetDimensions(qep,&nev,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);

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

  ierr = QEPGetTolerances(qep,&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

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

  ierr = QEPPrintSolution(qep,PETSC_NULL);CHKERRQ(ierr);

  ierr = QEPDestroy(&qep);CHKERRQ(ierr);

  ierr = MatDestroy(&M);CHKERRQ(ierr);

  ierr = MatDestroy(&C);CHKERRQ(ierr);

  ierr = MatDestroy(&K);CHKERRQ(ierr);

  ierr = SlepcFinalize();CHKERRQ(ierr);

  return 0;

}