/*
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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/>.
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*/
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
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/* 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
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/*
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
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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
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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;
}