Date: 2016-03-29T14:58:26+00:00

Actual source code: test16.c
slepc-3.6.3 2016-03-29
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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 a user-defined convergence test.\n\n";

     24: #include <slepceps.h>

     29: /*
     30:   MyConvergedAbsolute - Bizarre convergence test that requires more accuracy
     31:   to positive eigenvalues compared to negative ones.
     32: */
     33: PetscErrorCode MyConvergedAbsolute(EPS eps,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
     34: {
     36:   *errest = (PetscRealPart(eigr)<0.0)?res:100*res;
     37:   return(0);
     38: }

     42: int main(int argc,char **argv)
     43: {
     44:   Mat            A;           /* problem matrix */
     45:   EPS            eps;         /* eigenproblem solver context */
     46:   PetscInt       n=30,i,Istart,Iend;

     49:   SlepcInitialize(&argc,&argv,(char*)0,help);
     50:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
     51:   PetscPrintf(PETSC_COMM_WORLD,"\nTridiagonal Eigenproblem, n=%D\n\n",n);

     53:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     54:      Compute the operator matrix that defines the eigensystem, Ax=kx
     55:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     57:   MatCreate(PETSC_COMM_WORLD,&A);
     58:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
     59:   MatSetFromOptions(A);
     60:   MatSetUp(A);

     62:   MatGetOwnershipRange(A,&Istart,&Iend);
     63:   for (i=Istart;i<Iend;i++) {
     64:     if (i>0) { MatSetValue(A,i,i-1,-1.0,INSERT_VALUES); }
     65:     if (i<n-1) { MatSetValue(A,i,i+1,-1.0,INSERT_VALUES); }
     66:   }
     67:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     68:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
     69:   MatShift(A,-1e-3);

     71:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     72:                         Create the eigensolver
     73:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     74:   EPSCreate(PETSC_COMM_WORLD,&eps);
     75:   EPSSetOperators(eps,A,NULL);
     76:   EPSSetProblemType(eps,EPS_HEP);
     77:   /* set user-defined convergence test */
     78:   EPSSetConvergenceTestFunction(eps,MyConvergedAbsolute,NULL,NULL);
     79:   EPSSetFromOptions(eps);

     81:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     82:                           Solve the problem
     83:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     84:   EPSSolve(eps);
     85:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

     87:   EPSDestroy(&eps);
     88:   MatDestroy(&A);
     89:   SlepcFinalize();
     90:   return 0;
     91: }