Actual source code: ex25.c
slepc-3.5.2 2014-10-10
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2014, 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[] = "Spectrum slicing on generalized symmetric eigenproblem.\n\n"
23: "The problem is similar to ex13.c.\n\n"
24: "The command line options are:\n"
25: " -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
26: " -m <m>, where <m> = number of grid subdivisions in y dimension.\n";
28: #include <slepceps.h>
32: int main(int argc,char **argv)
33: {
34: Mat A,B; /* matrices */
35: EPS eps; /* eigenproblem solver context */
36: ST st; /* spectral transformation context */
37: KSP ksp;
38: PC pc;
39: EPSType type;
40: PetscInt N,n=10,m,Istart,Iend,II,nev,i,j;
41: PetscReal inta,intb;
42: PetscBool flag;
44: #if !defined(PETSC_HAVE_MUMPS)
45: PetscMPIInt size;
46: #endif
48: SlepcInitialize(&argc,&argv,(char*)0,help);
50: PetscOptionsGetInt(NULL,"-n",&n,NULL);
51: PetscOptionsGetInt(NULL,"-m",&m,&flag);
52: if (!flag) m=n;
53: N = n*m;
54: PetscPrintf(PETSC_COMM_WORLD,"\nSpectrum slicing on GHEP, N=%D (%Dx%D grid)\n\n",N,n,m);
56: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
57: Compute the matrices that define the eigensystem, Ax=kBx
58: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
60: MatCreate(PETSC_COMM_WORLD,&A);
61: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
62: MatSetFromOptions(A);
63: MatSetUp(A);
65: MatCreate(PETSC_COMM_WORLD,&B);
66: MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
67: MatSetFromOptions(B);
68: MatSetUp(B);
70: MatGetOwnershipRange(A,&Istart,&Iend);
71: for (II=Istart;II<Iend;II++) {
72: i = II/n; j = II-i*n;
73: if (i>0) { MatSetValue(A,II,II-n,-1.0,INSERT_VALUES); }
74: if (i<m-1) { MatSetValue(A,II,II+n,-1.0,INSERT_VALUES); }
75: if (j>0) { MatSetValue(A,II,II-1,-1.0,INSERT_VALUES); }
76: if (j<n-1) { MatSetValue(A,II,II+1,-1.0,INSERT_VALUES); }
77: MatSetValue(A,II,II,4.0,INSERT_VALUES);
78: MatSetValue(B,II,II,4.0,INSERT_VALUES);
79: }
81: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
82: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
83: MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
84: MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
86: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
87: Create the eigensolver and set various options
88: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
90: /*
91: Create eigensolver context
92: */
93: EPSCreate(PETSC_COMM_WORLD,&eps);
95: /*
96: Set operators and set problem type
97: */
98: EPSSetOperators(eps,A,B);
99: EPSSetProblemType(eps,EPS_GHEP);
101: /*
102: Set interval for spectrum slicing
103: */
104: inta = 0.1;
105: intb = 0.2;
106: EPSSetInterval(eps,inta,intb);
107: EPSSetWhichEigenpairs(eps,EPS_ALL);
109: /*
110: Set shift-and-invert with Cholesky; select MUMPS if available
111: */
113: EPSGetST(eps,&st);
114: STSetType(st,STSINVERT);
115:
116: STGetKSP(st,&ksp);
117: KSPSetType(ksp,KSPPREONLY);
118: KSPGetPC(ksp,&pc);
119: PCSetType(pc,PCCHOLESKY);
120:
121: #if defined(PETSC_HAVE_MUMPS)
122: #if defined(PETSC_USE_COMPLEX)
123: SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Spectrum slicing with MUMPS is not available for complex scalars");
124: #endif
125: PCFactorSetMatSolverPackage(pc,MATSOLVERMUMPS);
126: /*
127: must use runtime option '-mat_mumps_icntl_13 1' (turn off scaLAPACK for
128: matrix inertia), currently there is no better way of setting this in program
129: */
130: PetscOptionsInsertString("-mat_mumps_icntl_13 1");
131: #else
132: MPI_Comm_size(PETSC_COMM_WORLD,&size);
133: if (size>1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Configure with MUMPS if you want to run this example in parallel");
134: #endif
136: /*
137: Set solver parameters at runtime
138: */
139: EPSSetFromOptions(eps);
141: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
142: Solve the eigensystem
143: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
144: EPSSolve(eps);
146: /*
147: Show eigenvalues in interval and print solution
148: */
149: EPSGetType(eps,&type);
150: PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
151: EPSGetDimensions(eps,&nev,NULL,NULL);
152: EPSGetInterval(eps,&inta,&intb);
153: PetscPrintf(PETSC_COMM_WORLD," %D eigenvalues found in [%g, %g]\n",nev,(double)inta,(double)intb);
154: EPSPrintSolution(eps,NULL);
156: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
157: Clean up
158: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
159: EPSDestroy(&eps);
160: MatDestroy(&A);
161: MatDestroy(&B);
162: SlepcFinalize();
163: return 0;
164: }