Actual source code: test12.c
slepc-3.13.2 2020-05-12
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2020, 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. Illustrates use of shell preconditioner.\n\n"
12: "The command line options are:\n"
13: " -n <n>, where <n> = number of grid subdivisions = matrix dimension.\n"
14: " -seed <s>, where <s> = seed for random number generation.\n\n";
16: #include <slepceps.h>
18: PetscErrorCode PCApply_User(PC pc,Vec x,Vec y)
19: {
23: VecCopy(x,y);
24: return(0);
25: }
27: int main(int argc,char **argv)
28: {
29: Mat A; /* problem matrix */
30: EPS eps; /* eigenproblem solver context */
31: Vec v0; /* initial vector */
32: PetscRandom rand;
33: PetscReal tol=1000*PETSC_MACHINE_EPSILON;
34: PetscInt n=30,i,Istart,Iend,seed=0x12345678;
36: ST st;
37: KSP ksp;
38: PC pc;
40: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
42: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
43: PetscPrintf(PETSC_COMM_WORLD,"\nDiagonal Eigenproblem, n=%D\n\n",n);
45: MatCreate(PETSC_COMM_WORLD,&A);
46: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
47: MatSetFromOptions(A);
48: MatSetUp(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,NULL);
61: EPSSetProblemType(eps,EPS_HEP);
62: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
63: EPSSetFromOptions(eps);
64: EPSGetST(eps,&st);
65: STGetKSP(st,&ksp);
66: KSPGetPC(ksp,&pc);
67: PCSetType(pc,PCSHELL);
68: PCShellSetApply(pc,PCApply_User);
70: /* set random initial vector */
71: MatCreateVecs(A,&v0,NULL);
72: PetscRandomCreate(PETSC_COMM_WORLD,&rand);
73: PetscRandomSetFromOptions(rand);
74: PetscOptionsGetInt(NULL,NULL,"-seed",&seed,NULL);
75: PetscRandomSetSeed(rand,seed);
76: PetscRandomSeed(rand);
77: VecSetRandom(v0,rand);
78: EPSSetInitialSpace(eps,1,&v0);
79: /* call the solver */
80: EPSSolve(eps);
82: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
83: Display solution and clean up
84: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
85: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
86: EPSDestroy(&eps);
87: MatDestroy(&A);
88: VecDestroy(&v0);
89: PetscRandomDestroy(&rand);
90: SlepcFinalize();
91: return ierr;
92: }
94: /*TEST
96: testset:
97: requires: !single
98: output_file: output/test12_1.out
99: test:
100: suffix: 1
101: args: -eps_type {{krylovschur subspace arnoldi gd jd}} -eps_nev 4
102: test:
103: suffix: 1_power
104: args: -eps_type power -eps_max_it 10000 -eps_nev 4
105: test:
106: suffix: 1_gd2
107: args: -eps_type gd -eps_gd_double_expansion -eps_nev 4
109: TEST*/