Actual source code: test6.c
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2011, Universitat Politecnica de Valencia, Spain
6: This file is part of SLEPc.
7:
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[] = "Diagonal eigenproblem.\n\n"
23: "The command line options are:\n"
24: " -n <n>, where <n> = number of grid subdivisions = matrix dimension.\n"
25: " -seed <s>, where <s> = seed for random number generation.\n\n";
27: #include <slepceps.h>
31: int main(int argc,char **argv)
32: {
33: Mat A; /* problem matrix */
34: EPS eps; /* eigenproblem solver context */
35: Vec v0; /* initial vector */
36: PetscRandom rand;
37: PetscReal tol=1000*PETSC_MACHINE_EPSILON;
38: PetscInt n=30,i,Istart,Iend,seed=0x12345678;
41: SlepcInitialize(&argc,&argv,(char*)0,help);
43: PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);
44: PetscPrintf(PETSC_COMM_WORLD,"\nDiagonal Eigenproblem, n=%d\n\n",n);
46: MatCreate(PETSC_COMM_WORLD,&A);
47: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
48: MatSetFromOptions(A);
49: MatGetOwnershipRange(A,&Istart,&Iend);
50: for (i=Istart;i<Iend;i++) {
51: MatSetValue(A,i,i,i+1,INSERT_VALUES);
52: }
53: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
54: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
56: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
57: Solve the eigensystem
58: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
59: EPSCreate(PETSC_COMM_WORLD,&eps);
60: EPSSetOperators(eps,A,PETSC_NULL);
61: EPSSetProblemType(eps,EPS_HEP);
62: EPSSetTolerances(eps,tol,PETSC_DECIDE);
63: EPSSetFromOptions(eps);
64: /* set random initial vector */
65: MatGetVecs(A,&v0,PETSC_NULL);
66: PetscRandomCreate(PETSC_COMM_WORLD,&rand);
67: PetscRandomSetFromOptions(rand);
68: PetscOptionsGetInt(PETSC_NULL,"-seed",&seed,PETSC_NULL);
69: PetscRandomSetSeed(rand,seed);
70: PetscRandomSeed(rand);
71: VecSetRandom(v0,rand);
72: EPSSetInitialSpace(eps,1,&v0);
73: /* call the solver */
74: EPSSolve(eps);
76: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
77: Display solution and clean up
78: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
79: EPSPrintSolution(eps,PETSC_NULL);
80: EPSDestroy(&eps);
81: MatDestroy(&A);
82: VecDestroy(&v0);
83: PetscRandomDestroy(&rand);
84: SlepcFinalize();
85: return 0;
86: }