Date: 2015-09-03T15:05:03+00:00

Actual source code: test2.c
slepc-3.6.1 2015-09-03
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2015, 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=PetscMax(1000*PETSC_MACHINE_EPSILON,1e-9);
     34:   PetscInt       n=30,i,Istart,Iend;
     35:   PetscBool      flg;

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

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

     43:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     44:      Compute the operator matrix that defines the eigensystem, Ax=kx
     45:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

     52:   MatGetOwnershipRange(A,&Istart,&Iend);
     53:   for (i=Istart;i<Iend;i++) {
     54:     if (i>0) { MatSetValue(A,i,i-1,-1.0,INSERT_VALUES); }
     55:     if (i<n-1) { MatSetValue(A,i,i+1,-1.0,INSERT_VALUES); }
     56:     MatSetValue(A,i,i,2.0,INSERT_VALUES);
     57:   }
     58:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     59:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

     61:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     62:                         Create the eigensolver
     63:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     64:   EPSCreate(PETSC_COMM_WORLD,&eps);
     65:   EPSSetOperators(eps,A,NULL);
     66:   EPSSetProblemType(eps,EPS_HEP);
     67:   EPSSetTolerances(eps,tol,PETSC_DEFAULT);
     68:   EPSSetFromOptions(eps);

     70:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     71:                     Solve for largest eigenvalues
     72:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     73:   EPSSetWhichEigenpairs(eps,EPS_LARGEST_REAL);
     74:   EPSSolve(eps);
     75:   PetscPrintf(PETSC_COMM_WORLD," - - - Largest eigenvalues - - -\n");
     76:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

     78:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     79:                     Solve for smallest eigenvalues
     80:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     81:   EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL);
     82:   EPSSolve(eps);
     83:   PetscPrintf(PETSC_COMM_WORLD," - - - Smallest eigenvalues - - -\n");
     84:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

     86:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     87:                     Solve for interior eigenvalues (target=2.1)
     88:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     89:   EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE);
     90:   EPSSetTarget(eps,2.1);
     91:   PetscObjectTypeCompare((PetscObject)eps,EPSLANCZOS,&flg);
     92:   if (flg) {
     93:     EPSGetST(eps,&st);
     94:     STSetType(st,STSINVERT);
     95:   } else {
     96:     PetscObjectTypeCompare((PetscObject)eps,EPSKRYLOVSCHUR,&flg);
     97:     if (!flg) {
     98:       PetscObjectTypeCompare((PetscObject)eps,EPSARNOLDI,&flg);
     99:     }
    100:     if (flg) {
    101:       EPSSetExtraction(eps,EPS_HARMONIC);
    102:     }
    103:   }
    104:   EPSSolve(eps);
    105:   PetscPrintf(PETSC_COMM_WORLD," - - - Interior eigenvalues - - -\n");
    106:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

    108:   EPSDestroy(&eps);
    109:   MatDestroy(&A);
    110:   SlepcFinalize();
    111:   return 0;
    112: }