Actual source code: test20.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[] = "Tests multiple calls to EPSSolve changing ncv.\n\n";

 13: #include <slepceps.h>

 15: int main(int argc,char **argv)
 16: {
 17:   Mat            A;
 18:   EPS            eps;
 19:   PetscReal      tol=PetscMax(1000*PETSC_MACHINE_EPSILON,1e-9);
 20:   PetscInt       n=30,i,Istart,Iend,nev,ncv;

 23:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
 24:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 25:   PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian Eigenproblem, n=%D\n\n",n);

 27:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 28:      Compute the operator matrix that defines the eigensystem, Ax=kx
 29:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 31:   MatCreate(PETSC_COMM_WORLD,&A);
 32:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
 33:   MatSetFromOptions(A);
 34:   MatSetUp(A);
 35:   MatGetOwnershipRange(A,&Istart,&Iend);
 36:   for (i=Istart;i<Iend;i++) {
 37:     if (i>0) { MatSetValue(A,i,i-1,-1.0,INSERT_VALUES); }
 38:     if (i<n-1) { MatSetValue(A,i,i+1,-1.0,INSERT_VALUES); }
 39:     MatSetValue(A,i,i,2.0,INSERT_VALUES);
 40:   }
 41:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 42:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 44:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 45:              Create the solver, call EPSSolve() twice
 46:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 47:   EPSCreate(PETSC_COMM_WORLD,&eps);
 48:   EPSSetOperators(eps,A,NULL);
 49:   EPSSetProblemType(eps,EPS_HEP);
 50:   EPSSetTolerances(eps,tol,PETSC_DEFAULT);
 51:   EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL);
 52:   EPSSetFromOptions(eps);

 54:   /* First solve */
 55:   EPSSolve(eps);
 56:   PetscPrintf(PETSC_COMM_WORLD," - - - First solve, default subspace dimension - - -\n");
 57:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

 59:   /* Second solve */
 60:   EPSGetDimensions(eps,&nev,&ncv,NULL);
 61:   EPSSetDimensions(eps,nev,ncv+2,PETSC_DEFAULT);
 62:   EPSSolve(eps);
 63:   PetscPrintf(PETSC_COMM_WORLD," - - - Second solve, subspace of increased size - - -\n");
 64:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

 66:   EPSDestroy(&eps);
 67:   MatDestroy(&A);
 68:   SlepcFinalize();
 69:   return ierr;
 70: }

 72: /*TEST

 74:    test:
 75:       suffix: 1
 76:       args: -n 18 -eps_type {{krylovschur arnoldi gd jd rqcg lobpcg lapack}} -eps_max_it 1500
 77:       output_file: output/test20_1.out

 79:    test:
 80:       suffix: 1_lanczos
 81:       args: -n 18 -eps_type lanczos -eps_lanczos_reorthog full -eps_max_it 1500
 82:       output_file: output/test20_1.out

 84: TEST*/