Actual source code: test16.c
slepc-3.6.1 2015-09-03
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2015, Universitat Politecnica de Valencia, Spain
6: This file is part of SLEPc.
8: SLEPc is free software: you can redistribute it and/or modify it under the
9: terms of version 3 of the GNU Lesser General Public License as published by
10: the Free Software Foundation.
12: SLEPc is distributed in the hope that it will be useful, but WITHOUT ANY
13: WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14: FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
15: more details.
17: You should have received a copy of the GNU Lesser General Public License
18: along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
19: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
20: */
22: static char help[] = "Tests a user-defined convergence test.\n\n";
24: #include <slepceps.h>
29: /*
30: MyConvergedAbsolute - Bizarre convergence test that requires more accuracy
31: to positive eigenvalues compared to negative ones.
32: */
33: PetscErrorCode MyConvergedAbsolute(EPS eps,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
34: {
36: *errest = (PetscRealPart(eigr)<0.0)?res:100*res;
37: return(0);
38: }
42: int main(int argc,char **argv)
43: {
44: Mat A; /* problem matrix */
45: EPS eps; /* eigenproblem solver context */
46: PetscInt n=30,i,Istart,Iend;
49: SlepcInitialize(&argc,&argv,(char*)0,help);
50: PetscOptionsGetInt(NULL,"-n",&n,NULL);
51: PetscPrintf(PETSC_COMM_WORLD,"\nTridiagonal Eigenproblem, n=%D\n\n",n);
53: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
54: Compute the operator matrix that defines the eigensystem, Ax=kx
55: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
57: MatCreate(PETSC_COMM_WORLD,&A);
58: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
59: MatSetFromOptions(A);
60: MatSetUp(A);
62: MatGetOwnershipRange(A,&Istart,&Iend);
63: for (i=Istart;i<Iend;i++) {
64: if (i>0) { MatSetValue(A,i,i-1,-1.0,INSERT_VALUES); }
65: if (i<n-1) { MatSetValue(A,i,i+1,-1.0,INSERT_VALUES); }
66: }
67: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
68: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
69: MatShift(A,-1e-3);
71: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
72: Create the eigensolver
73: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
74: EPSCreate(PETSC_COMM_WORLD,&eps);
75: EPSSetOperators(eps,A,NULL);
76: EPSSetProblemType(eps,EPS_HEP);
77: /* set user-defined convergence test */
78: EPSSetConvergenceTestFunction(eps,MyConvergedAbsolute,NULL,NULL);
79: EPSSetFromOptions(eps);
81: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
82: Solve the problem
83: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
84: EPSSolve(eps);
85: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
87: EPSDestroy(&eps);
88: MatDestroy(&A);
89: SlepcFinalize();
90: return 0;
91: }