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

Actual source code: test1.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 B-orthonormality of eigenvectors in a GHEP problem.\n\n";

     24: #include <slepceps.h>

     28: int main(int argc,char **argv)
     29: {
     30:   Mat            A,B;        /* matrices */
     31:   EPS            eps;        /* eigenproblem solver context */
     32:   Vec            *X,v;
     33:   PetscReal      lev,tol=1000*PETSC_MACHINE_EPSILON;
     34:   PetscInt       N,n=45,m,Istart,Iend,II,i,j,nconv;
     35:   PetscBool      flag;

     38:   SlepcInitialize(&argc,&argv,(char*)0,help);
     39:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
     40:   PetscOptionsGetInt(NULL,"-m",&m,&flag);
     41:   if (!flag) m=n;
     42:   N = n*m;
     43:   PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized Symmetric Eigenproblem, N=%D (%Dx%D grid)\n\n",N,n,m);

     45:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     46:      Compute the matrices that define the eigensystem, Ax=kBx
     47:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

     54:   MatCreate(PETSC_COMM_WORLD,&B);
     55:   MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
     56:   MatSetFromOptions(B);
     57:   MatSetUp(B);

     59:   MatGetOwnershipRange(A,&Istart,&Iend);
     60:   for (II=Istart;II<Iend;II++) {
     61:     i = II/n; j = II-i*n;
     62:     if (i>0) { MatSetValue(A,II,II-n,-1.0,INSERT_VALUES); }
     63:     if (i<m-1) { MatSetValue(A,II,II+n,-1.0,INSERT_VALUES); }
     64:     if (j>0) { MatSetValue(A,II,II-1,-1.0,INSERT_VALUES); }
     65:     if (j<n-1) { MatSetValue(A,II,II+1,-1.0,INSERT_VALUES); }
     66:     MatSetValue(A,II,II,4.0,INSERT_VALUES);
     67:     MatSetValue(B,II,II,2.0/PetscLogScalar(II+2),INSERT_VALUES);
     68:   }

     70:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     71:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
     72:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
     73:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
     74:   MatCreateVecs(B,&v,NULL);

     76:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     77:                 Create the eigensolver and set various options
     78:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     80:   EPSCreate(PETSC_COMM_WORLD,&eps);
     81:   EPSSetOperators(eps,A,B);
     82:   EPSSetProblemType(eps,EPS_GHEP);
     83:   EPSSetTolerances(eps,tol,PETSC_DEFAULT);
     84:   EPSSetFromOptions(eps);

     86:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     87:                       Solve the eigensystem
     88:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     90:   EPSSolve(eps);

     92:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     93:                     Display solution and clean up
     94:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     96:   EPSGetTolerances(eps,&tol,NULL);
     97:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
     98:   EPSGetConverged(eps,&nconv);
     99:   if (nconv>0) {
    100:     VecDuplicateVecs(v,nconv,&X);
    101:     for (i=0;i<nconv;i++) {
    102:       EPSGetEigenvector(eps,i,X[i],NULL);
    103:     }
    104:     SlepcCheckOrthogonality(X,nconv,NULL,nconv,B,NULL,&lev);
    105:     if (lev<10*tol) {
    106:       PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality below the tolerance\n");
    107:     } else {
    108:       PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality: %g\n",(double)lev);
    109:     }
    110:     VecDestroyVecs(nconv,&X);
    111:   }

    113:   EPSDestroy(&eps);
    114:   MatDestroy(&A);
    115:   MatDestroy(&B);
    116:   VecDestroy(&v);
    117:   SlepcFinalize();
    118:   return 0;
    119: }