Date: 2024-04-26T10:21:59+00:00

Actual source code: test13.c
slepc-3.21.1 2024-04-26
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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 EPSSetArbitrarySelection.\n\n";

     13: #include <slepceps.h>

     15: PetscErrorCode MyArbitrarySelection(PetscScalar eigr,PetscScalar eigi,Vec xr,Vec xi,PetscScalar *rr,PetscScalar *ri,void *ctx)
     16: {
     17:   Vec             xref = *(Vec*)ctx;

     19:   PetscFunctionBeginUser;
     20:   PetscCall(VecDot(xr,xref,rr));
     21:   *rr = PetscAbsScalar(*rr);
     22:   if (ri) *ri = 0.0;
     23:   PetscFunctionReturn(PETSC_SUCCESS);
     24: }

     26: int main(int argc,char **argv)
     27: {
     28:   Mat            A;           /* problem matrices */
     29:   EPS            eps;         /* eigenproblem solver context */
     30:   PetscScalar    seigr,seigi;
     31:   PetscReal      tol=1000*PETSC_MACHINE_EPSILON;
     32:   Vec            sxr,sxi;
     33:   PetscInt       n=30,i,Istart,Iend,nconv;

     35:   PetscFunctionBeginUser;
     36:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));

     38:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     39:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nTridiagonal with zero diagonal, n=%" PetscInt_FMT "\n\n",n));

     41:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     42:            Create matrix tridiag([-1 0 -1])
     43:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     44:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
     45:   PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n));
     46:   PetscCall(MatSetFromOptions(A));

     48:   PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
     49:   for (i=Istart;i<Iend;i++) {
     50:     if (i>0) PetscCall(MatSetValue(A,i,i-1,-1.0,INSERT_VALUES));
     51:     if (i<n-1) PetscCall(MatSetValue(A,i,i+1,-1.0,INSERT_VALUES));
     52:   }
     53:   PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
     54:   PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));

     56:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     57:                         Create the eigensolver
     58:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     59:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
     60:   PetscCall(EPSSetProblemType(eps,EPS_HEP));
     61:   PetscCall(EPSSetTolerances(eps,tol,PETSC_DEFAULT));
     62:   PetscCall(EPSSetOperators(eps,A,NULL));
     63:   PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL));
     64:   PetscCall(EPSSetFromOptions(eps));

     66:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     67:                 Solve eigenproblem and store some solution
     68:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     69:   PetscCall(EPSSolve(eps));
     70:   PetscCall(MatCreateVecs(A,&sxr,NULL));
     71:   PetscCall(MatCreateVecs(A,&sxi,NULL));
     72:   PetscCall(EPSGetConverged(eps,&nconv));
     73:   if (nconv>0) {
     74:     PetscCall(EPSGetEigenpair(eps,0,&seigr,&seigi,sxr,sxi));
     75:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));

     77:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     78:                  Solve eigenproblem using an arbitrary selection
     79:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     80:     PetscCall(EPSSetArbitrarySelection(eps,MyArbitrarySelection,&sxr));
     81:     PetscCall(EPSSetWhichEigenpairs(eps,EPS_LARGEST_MAGNITUDE));
     82:     PetscCall(EPSSolve(eps));
     83:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
     84:   } else PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Problem: no eigenpairs converged.\n"));

     86:   PetscCall(EPSDestroy(&eps));
     87:   PetscCall(VecDestroy(&sxr));
     88:   PetscCall(VecDestroy(&sxi));
     89:   PetscCall(MatDestroy(&A));
     90:   PetscCall(SlepcFinalize());
     91:   return 0;
     92: }

     94: /*TEST

     96:    testset:
     97:       args: -eps_max_it 5000 -st_pc_type jacobi
     98:       output_file: output/test13_1.out
     99:       filter: sed -e "s/-1.98975/-1.98974/"
    100:       test:
    101:          suffix: 1
    102:          args: -eps_type {{krylovschur gd}}
    103:       test:
    104:          suffix: 1_jd
    105:          args: -eps_type jd -st_ksp_type gmres
    106:       test:
    107:          suffix: 1_gd2
    108:          args: -eps_type gd -eps_gd_double_expansion
    109:       test:
    110:          suffix: 2
    111:          args: -eps_non_hermitian -eps_type {{krylovschur gd jd}}
    112:       test:
    113:          suffix: 2_gd2
    114:          args: -eps_non_hermitian -eps_type gd -eps_gd_double_expansion
    115:          timeoutfactor: 2

    117: TEST*/