Actual source code: test6.c
slepc-3.18.1 2022-11-02
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[] = "Diagonal eigenproblem.\n\n"
12: "The command line options are:\n"
13: " -n <n>, where <n> = matrix dimension.\n"
14: " -seed <s>, where <s> = seed for random number generation.\n\n";
16: #include <slepceps.h>
18: int main(int argc,char **argv)
19: {
20: Mat A; /* problem matrix */
21: EPS eps; /* eigenproblem solver context */
22: Vec v0; /* initial vector */
23: PetscRandom rand;
24: PetscReal tol=PETSC_SMALL;
25: PetscInt n=30,i,Istart,Iend,seed=0x12345678;
28: SlepcInitialize(&argc,&argv,(char*)0,help);
30: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
31: PetscPrintf(PETSC_COMM_WORLD,"\nDiagonal Eigenproblem, n=%" PetscInt_FMT "\n\n",n);
33: MatCreate(PETSC_COMM_WORLD,&A);
34: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
35: MatSetFromOptions(A);
36: MatSetUp(A);
37: MatGetOwnershipRange(A,&Istart,&Iend);
38: for (i=Istart;i<Iend;i++) MatSetValue(A,i,i,i+1,INSERT_VALUES);
39: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
40: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
42: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
43: Solve the eigensystem
44: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
45: EPSCreate(PETSC_COMM_WORLD,&eps);
46: EPSSetOperators(eps,A,NULL);
47: EPSSetProblemType(eps,EPS_HEP);
48: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
49: EPSSetFromOptions(eps);
50: /* set random initial vector */
51: MatCreateVecs(A,&v0,NULL);
52: PetscRandomCreate(PETSC_COMM_WORLD,&rand);
53: PetscRandomSetFromOptions(rand);
54: PetscOptionsGetInt(NULL,NULL,"-seed",&seed,NULL);
55: PetscRandomSetSeed(rand,seed);
56: PetscRandomSeed(rand);
57: VecSetRandom(v0,rand);
58: EPSSetInitialSpace(eps,1,&v0);
59: /* call the solver */
60: EPSSolve(eps);
62: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
63: Display solution and clean up
64: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
65: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
66: EPSDestroy(&eps);
67: MatDestroy(&A);
68: VecDestroy(&v0);
69: PetscRandomDestroy(&rand);
70: SlepcFinalize();
71: return 0;
72: }
74: /*TEST
76: testset:
77: args: -eps_nev 4
78: requires: !single
79: output_file: output/test6_1.out
80: test:
81: suffix: 1
82: args: -eps_type {{krylovschur subspace arnoldi gd}}
83: test:
84: suffix: 1_power
85: args: -eps_type power -eps_max_it 20000
86: test:
87: suffix: 1_gd2
88: args: -eps_type gd -eps_gd_double_expansion
89: test:
90: suffix: 1_arpack
91: args: -eps_type arpack
92: requires: arpack
93: test:
94: suffix: 1_trlan
95: args: -eps_type trlan
96: requires: trlan
98: TEST*/