Actual source code: test20.c
slepc-3.19.2 2023-09-05
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[] = "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;
22: PetscFunctionBeginUser;
23: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
24: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
25: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian Eigenproblem, n=%" PetscInt_FMT "\n\n",n));
27: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
28: Compute the operator matrix that defines the eigensystem, Ax=kx
29: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
31: PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
32: PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n));
33: PetscCall(MatSetFromOptions(A));
34: PetscCall(MatSetUp(A));
35: PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
36: for (i=Istart;i<Iend;i++) {
37: if (i>0) PetscCall(MatSetValue(A,i,i-1,-1.0,INSERT_VALUES));
38: if (i<n-1) PetscCall(MatSetValue(A,i,i+1,-1.0,INSERT_VALUES));
39: PetscCall(MatSetValue(A,i,i,2.0,INSERT_VALUES));
40: }
41: PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
42: PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
44: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
45: Create the solver, call EPSSolve() twice
46: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
47: PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
48: PetscCall(EPSSetOperators(eps,A,NULL));
49: PetscCall(EPSSetProblemType(eps,EPS_HEP));
50: PetscCall(EPSSetTolerances(eps,tol,PETSC_DEFAULT));
51: PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL));
52: PetscCall(EPSSetFromOptions(eps));
54: /* First solve */
55: PetscCall(EPSSolve(eps));
56: PetscCall(PetscPrintf(PETSC_COMM_WORLD," - - - First solve, default subspace dimension - - -\n"));
57: PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
59: /* Second solve */
60: PetscCall(EPSGetDimensions(eps,&nev,&ncv,NULL));
61: PetscCall(EPSSetDimensions(eps,nev,ncv+2,PETSC_DEFAULT));
62: PetscCall(EPSSolve(eps));
63: PetscCall(PetscPrintf(PETSC_COMM_WORLD," - - - Second solve, subspace of increased size - - -\n"));
64: PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
66: PetscCall(EPSDestroy(&eps));
67: PetscCall(MatDestroy(&A));
68: PetscCall(SlepcFinalize());
69: return 0;
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*/