Actual source code: test20.c
slepc-3.17.0 2022-03-31
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: SlepcInitialize(&argc,&argv,(char*)0,help);
23: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
24: PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian Eigenproblem, n=%" PetscInt_FMT "\n\n",n);
26: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
27: Compute the operator matrix that defines the eigensystem, Ax=kx
28: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
30: MatCreate(PETSC_COMM_WORLD,&A);
31: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
32: MatSetFromOptions(A);
33: MatSetUp(A);
34: MatGetOwnershipRange(A,&Istart,&Iend);
35: for (i=Istart;i<Iend;i++) {
36: if (i>0) MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
37: if (i<n-1) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
38: MatSetValue(A,i,i,2.0,INSERT_VALUES);
39: }
40: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
41: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
43: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
44: Create the solver, call EPSSolve() twice
45: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
46: EPSCreate(PETSC_COMM_WORLD,&eps);
47: EPSSetOperators(eps,A,NULL);
48: EPSSetProblemType(eps,EPS_HEP);
49: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
50: EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL);
51: EPSSetFromOptions(eps);
53: /* First solve */
54: EPSSolve(eps);
55: PetscPrintf(PETSC_COMM_WORLD," - - - First solve, default subspace dimension - - -\n");
56: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
58: /* Second solve */
59: EPSGetDimensions(eps,&nev,&ncv,NULL);
60: EPSSetDimensions(eps,nev,ncv+2,PETSC_DEFAULT);
61: EPSSolve(eps);
62: PetscPrintf(PETSC_COMM_WORLD," - - - Second solve, subspace of increased size - - -\n");
63: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
65: EPSDestroy(&eps);
66: MatDestroy(&A);
67: SlepcFinalize();
68: return 0;
69: }
71: /*TEST
73: test:
74: suffix: 1
75: args: -n 18 -eps_type {{krylovschur arnoldi gd jd rqcg lobpcg lapack}} -eps_max_it 1500
76: output_file: output/test20_1.out
78: test:
79: suffix: 1_lanczos
80: args: -n 18 -eps_type lanczos -eps_lanczos_reorthog full -eps_max_it 1500
81: output_file: output/test20_1.out
83: TEST*/