Date: 2023-11-27T17:18:35+00:00

Actual source code: test30.c
slepc-3.20.1 2023-11-27
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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;

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

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

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

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

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

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