Date: 2022-11-02T11:46:58+00:00

Actual source code: test30.c
slepc-3.18.1 2022-11-02
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */

     11: static char help[] = "Test changing EPS type.\n\n";

     13: #include <slepceps.h>

     15: int main(int argc,char **argv)
     16: {
     17:   Mat            A;           /* problem matrix */
     18:   EPS            eps;         /* eigenproblem solver context */
     19:   ST             st;
     20:   KSP            ksp;
     21:   PetscInt       n=20,i,Istart,Iend,nrest;

     24:   SlepcInitialize(&argc,&argv,(char*)0,help);
     25:   PetscPrintf(PETSC_COMM_WORLD,"\nDiagonal Eigenproblem, n=%" PetscInt_FMT "\n\n",n);

     27:   MatCreate(PETSC_COMM_WORLD,&A);
     28:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
     29:   MatSetFromOptions(A);
     30:   MatSetUp(A);
     31:   MatGetOwnershipRange(A,&Istart,&Iend);
     32:   for (i=Istart;i<Iend;i++) MatSetValue(A,i,i,i+1,INSERT_VALUES);
     33:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     34:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

     36:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     37:              Create eigensolver and view options
     38:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     39:   EPSCreate(PETSC_COMM_WORLD,&eps);
     40:   EPSSetOperators(eps,A,NULL);
     41:   EPSSetProblemType(eps,EPS_HEP);
     42:   EPSSetTarget(eps,4.8);
     43:   EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE);
     44:   EPSSetDimensions(eps,4,PETSC_DEFAULT,PETSC_DEFAULT);

     46:   EPSSetType(eps,EPSRQCG);
     47:   EPSRQCGSetReset(eps,10);
     48:   EPSSetFromOptions(eps);
     49:   EPSRQCGGetReset(eps,&nrest);
     50:   PetscPrintf(PETSC_COMM_WORLD,"RQCG reset parameter = %" PetscInt_FMT "\n\n",nrest);
     51:   EPSView(eps,NULL);

     53:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     54:              Change eigensolver type and solve problem
     55:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     56:   EPSSetType(eps,EPSGD);
     57:   EPSGetST(eps,&st);
     58:   STGetKSP(st,&ksp);
     59:   KSPSetType(ksp,KSPPREONLY);
     60:   EPSSolve(eps);
     61:   EPSView(eps,NULL);

     63:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     64:                     Display solution and clean up
     65:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     66:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
     67:   EPSDestroy(&eps);
     68:   MatDestroy(&A);
     69:   SlepcFinalize();
     70:   return 0;
     71: }

     73: /*TEST

     75:    test:
     76:       suffix: 1
     77:       args: -eps_harmonic -eps_conv_norm
     78:       filter: grep -v tolerance | sed -e "s/symmetric/hermitian/"

     80: TEST*/