Actual source code: test4.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[] = "Test the solution of a HEP without calling EPSSetFromOptions (based on ex1.c).\n\n"
23: "The command line options are:\n"
24: " -n <n>, where <n> = number of grid subdivisions = matrix dimension.\n"
25: " -type <eps_type> = eps type to test.\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: const EPSType type;
36: PetscReal tol=1000*PETSC_MACHINE_EPSILON;
37: PetscScalar value[3];
38: PetscInt n=30,i,Istart,Iend,col[3],nev;
39: PetscBool FirstBlock=PETSC_FALSE,LastBlock=PETSC_FALSE;
40: char epstype[30] = "krylovschur";
43: SlepcInitialize(&argc,&argv,(char*)0,help);
45: PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);
46: PetscOptionsGetString(PETSC_NULL,"-type",epstype,30,PETSC_NULL);
47: PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian Eigenproblem, n=%D",n);
48: PetscPrintf(PETSC_COMM_WORLD,"\nEPS type: %s\n\n",epstype);
50: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
51: Compute the operator matrix that defines the eigensystem, Ax=kx
52: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
54: MatCreate(PETSC_COMM_WORLD,&A);
55: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
56: MatSetFromOptions(A);
57:
58: MatGetOwnershipRange(A,&Istart,&Iend);
59: if (Istart==0) FirstBlock=PETSC_TRUE;
60: if (Iend==n) LastBlock=PETSC_TRUE;
61: value[0]=-1.0; value[1]=2.0; value[2]=-1.0;
62: for (i=(FirstBlock? Istart+1: Istart); i<(LastBlock? Iend-1: Iend); i++) {
63: col[0]=i-1; col[1]=i; col[2]=i+1;
64: MatSetValues(A,1,&i,3,col,value,INSERT_VALUES);
65: }
66: if (LastBlock) {
67: i=n-1; col[0]=n-2; col[1]=n-1;
68: MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
69: }
70: if (FirstBlock) {
71: i=0; col[0]=0; col[1]=1; value[0]=2.0; value[1]=-1.0;
72: MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
73: }
75: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
76: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
78: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
79: Create the eigensolver and set various options
80: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
81: /*
82: Create eigensolver context
83: */
84: EPSCreate(PETSC_COMM_WORLD,&eps);
86: /*
87: Set operators. In this case, it is a standard eigenvalue problem
88: */
89: EPSSetOperators(eps,A,PETSC_NULL);
90: EPSSetProblemType(eps,EPS_HEP);
91: EPSSetDimensions(eps,4,PETSC_DEFAULT,PETSC_DEFAULT);
92: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
94: /*
95: Set solver parameters at runtime
96: */
97: EPSSetType(eps,epstype);
99: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
100: Solve the eigensystem
101: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
103: EPSSolve(eps);
104: /*
105: Optional: Get some information from the solver and display it
106: */
107: EPSGetType(eps,&type);
108: PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
109: EPSGetDimensions(eps,&nev,PETSC_NULL,PETSC_NULL);
110: PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
112: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
113: Display solution and clean up
114: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
116: EPSPrintSolution(eps,PETSC_NULL);
117: EPSDestroy(&eps);
118: MatDestroy(&A);
119: SlepcFinalize();
120: return 0;
121: }