Actual source code: test16.c
slepc-3.18.2 2023-01-26
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 a user-defined convergence test.\n\n";
13: #include <slepceps.h>
15: /*
16: MyConvergedAbsolute - Bizarre convergence test that requires more accuracy
17: to positive eigenvalues compared to negative ones.
18: */
19: PetscErrorCode MyConvergedAbsolute(EPS eps,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
20: {
21: *errest = (PetscRealPart(eigr)<0.0)?res:100*res;
22: return 0;
23: }
25: int main(int argc,char **argv)
26: {
27: Mat A; /* problem matrix */
28: EPS eps; /* eigenproblem solver context */
29: PetscInt n=30,i,Istart,Iend;
32: SlepcInitialize(&argc,&argv,(char*)0,help);
33: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
34: PetscPrintf(PETSC_COMM_WORLD,"\nTridiagonal Eigenproblem, n=%" PetscInt_FMT "\n\n",n);
36: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
37: Compute the operator matrix that defines the eigensystem, Ax=kx
38: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
40: MatCreate(PETSC_COMM_WORLD,&A);
41: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
42: MatSetFromOptions(A);
43: MatSetUp(A);
45: MatGetOwnershipRange(A,&Istart,&Iend);
46: for (i=Istart;i<Iend;i++) {
47: if (i>0) MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
48: if (i<n-1) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
49: }
50: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
51: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
52: MatShift(A,-1e-3);
54: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
55: Create the eigensolver
56: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
57: EPSCreate(PETSC_COMM_WORLD,&eps);
58: EPSSetOperators(eps,A,NULL);
59: EPSSetProblemType(eps,EPS_HEP);
60: /* set user-defined convergence test */
61: EPSSetConvergenceTestFunction(eps,MyConvergedAbsolute,NULL,NULL);
62: EPSSetFromOptions(eps);
64: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
65: Solve the problem
66: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
67: EPSSolve(eps);
68: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
70: EPSDestroy(&eps);
71: MatDestroy(&A);
72: SlepcFinalize();
73: return 0;
74: }
76: /*TEST
78: test:
79: suffix: 1
80: args: -n 200 -eps_nev 6 -eps_ncv 24 -eps_smallest_magnitude
81: requires: !single
83: TEST*/