Actual source code: test13.c

slepc-3.11.2 2019-07-30
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2019, 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:   PetscErrorCode  ierr;
 18:   Vec             xref = *(Vec*)ctx;

 21:   VecDot(xr,xref,rr);
 22:   *rr = PetscAbsScalar(*rr);
 23:   if (ri) *ri = 0.0;
 24:   return(0);
 25: }

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

 37:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;

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

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

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

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

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

 79:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 80:                  Solve eigenproblem using an arbitrary selection
 81:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 82:     EPSSetArbitrarySelection(eps,MyArbitrarySelection,&sxr);
 83:     EPSSetWhichEigenpairs(eps,EPS_LARGEST_MAGNITUDE);
 84:     EPSSolve(eps);
 85:     EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
 86:   } else {
 87:     PetscPrintf(PETSC_COMM_WORLD,"Problem: no eigenpairs converged.\n");
 88:   }

 90:   EPSDestroy(&eps);
 91:   VecDestroy(&sxr);
 92:   VecDestroy(&sxi);
 93:   MatDestroy(&A);
 94:   SlepcFinalize();
 95:   return ierr;
 96: }

 98: /*TEST

100:    testset:
101:       args: -eps_max_it 5000
102:       output_file: output/test13_1.out
103:       test:
104:          suffix: 1
105:          args: -eps_type {{krylovschur gd jd}}
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*/