Date: 2013-09-02T10:05:21+00:00

Actual source code: test2.c

      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2013, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.

      8:    SLEPc is free software: you can redistribute it and/or modify it under  the
      9:    terms of version 3 of the GNU Lesser General Public License as published by
     10:    the Free Software Foundation.

     12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
     13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
     14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
     15:    more details.

     17:    You  should have received a copy of the GNU Lesser General  Public  License
     18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
     19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     20: */

     22: static char help[] = "Tests multiple calls to EPSSolve with the same matrix.\n\n";

     24: #include <slepceps.h>

     28: int main(int argc,char **argv)
     29: {
     30:   Mat            A;           /* problem matrix */
     31:   EPS            eps;         /* eigenproblem solver context */
     32:   ST             st;
     33:   PetscReal      tol=1000*PETSC_MACHINE_EPSILON;
     34:   PetscScalar    value[3];
     35:   PetscInt       n=30,i,Istart,Iend,col[3];
     36:   PetscBool      FirstBlock=PETSC_FALSE,LastBlock=PETSC_FALSE,flg;

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

     41:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
     42:   PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian Eigenproblem, n=%D\n\n",n);

     44:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     45:      Compute the operator matrix that defines the eigensystem, Ax=kx
     46:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     48:   MatCreate(PETSC_COMM_WORLD,&A);
     49:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
     50:   MatSetFromOptions(A);
     51:   MatSetUp(A);

     53:   MatGetOwnershipRange(A,&Istart,&Iend);
     54:   if (Istart==0) FirstBlock=PETSC_TRUE;
     55:   if (Iend==n) LastBlock=PETSC_TRUE;
     56:   value[0]=-1.0; value[1]=2.0; value[2]=-1.0;
     57:   for (i=(FirstBlock? Istart+1: Istart); i<(LastBlock? Iend-1: Iend); i++) {
     58:     col[0]=i-1; col[1]=i; col[2]=i+1;
     59:     MatSetValues(A,1,&i,3,col,value,INSERT_VALUES);
     60:   }
     61:   if (LastBlock) {
     62:     i=n-1; col[0]=n-2; col[1]=n-1;
     63:     MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
     64:   }
     65:   if (FirstBlock) {
     66:     i=0; col[0]=0; col[1]=1; value[0]=2.0; value[1]=-1.0;
     67:     MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
     68:   }

     70:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     71:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

     73:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     74:                         Create the eigensolver
     75:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     76:   EPSCreate(PETSC_COMM_WORLD,&eps);
     77:   EPSSetOperators(eps,A,NULL);
     78:   EPSSetProblemType(eps,EPS_HEP);
     79:   EPSSetTolerances(eps,tol,PETSC_DECIDE);
     80:   EPSSetFromOptions(eps);

     82:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     83:                     Solve for largest eigenvalues
     84:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     85:   EPSSetWhichEigenpairs(eps,EPS_LARGEST_REAL);
     86:   EPSSolve(eps);
     87:   PetscPrintf(PETSC_COMM_WORLD," - - - Largest eigenvalues - - -\n");
     88:   EPSPrintSolution(eps,NULL);

     90:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     91:                     Solve for smallest eigenvalues
     92:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     93:   EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL);
     94:   EPSSolve(eps);
     95:   PetscPrintf(PETSC_COMM_WORLD," - - - Smallest eigenvalues - - -\n");
     96:   EPSPrintSolution(eps,NULL);

     98:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     99:                     Solve for interior eigenvalues (target=2.1)
    100:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    101:   EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE);
    102:   EPSSetTarget(eps,2.1);
    103:   PetscObjectTypeCompare((PetscObject)eps,EPSLANCZOS,&flg);
    104:   if (flg) {
    105:     EPSGetST(eps,&st);
    106:     STSetType(st,STSINVERT);
    107:   } else {
    108:     PetscObjectTypeCompare((PetscObject)eps,EPSKRYLOVSCHUR,&flg);
    109:     if (!flg) {
    110:       PetscObjectTypeCompare((PetscObject)eps,EPSARNOLDI,&flg);
    111:     }
    112:     if (flg) {
    113:       EPSSetExtraction(eps,EPS_HARMONIC);
    114:     }
    115:   }
    116:   EPSSolve(eps);
    117:   PetscPrintf(PETSC_COMM_WORLD," - - - Interior eigenvalues - - -\n");
    118:   EPSPrintSolution(eps,NULL);

    120:   EPSDestroy(&eps);
    121:   MatDestroy(&A);
    122:   SlepcFinalize();
    123:   return 0;
    124: }