Actual source code: ex43.c
slepc-3.21.0 2024-03-30
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[] = "Generalized eigenproblem, illustrates setting MUMPS options.\n\n"
12: "The problem is Ax = lambda Bx, with:\n"
13: " A = Laplacian operator in 2-D\n"
14: " B = diagonal matrix with all values equal to 4\n\n"
15: "The command line options are:\n"
16: " -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
17: " -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";
19: #include <slepceps.h>
21: int main(int argc,char **argv)
22: {
23: Mat A,B;
24: #if defined(PETSC_HAVE_MUMPS)
25: Mat K;
26: #endif
27: EPS eps;
28: EPSType type;
29: ST st;
30: KSP ksp;
31: PC pc;
32: PetscInt N,n=10,m=12,Istart,Iend,II,nev,i,j;
33: PetscBool flag,terse;
35: PetscFunctionBeginUser;
36: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
38: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
39: PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
40: N = n*m;
41: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));
43: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
44: Compute the matrices that define the eigensystem, Ax=kBx
45: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
47: PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
48: PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N));
49: PetscCall(MatSetFromOptions(A));
51: PetscCall(MatCreate(PETSC_COMM_WORLD,&B));
52: PetscCall(MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N));
53: PetscCall(MatSetFromOptions(B));
55: PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
56: for (II=Istart;II<Iend;II++) {
57: i = II/n; j = II-i*n;
58: if (i>0) PetscCall(MatSetValue(A,II,II-n,-1.0,INSERT_VALUES));
59: if (i<m-1) PetscCall(MatSetValue(A,II,II+n,-1.0,INSERT_VALUES));
60: if (j>0) PetscCall(MatSetValue(A,II,II-1,-1.0,INSERT_VALUES));
61: if (j<n-1) PetscCall(MatSetValue(A,II,II+1,-1.0,INSERT_VALUES));
62: PetscCall(MatSetValue(A,II,II,4.0,INSERT_VALUES));
63: PetscCall(MatSetValue(B,II,II,4.0,INSERT_VALUES));
64: }
66: PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
67: PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
68: PetscCall(MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY));
69: PetscCall(MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY));
71: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
72: Create the eigensolver and set various options
73: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
75: /*
76: Create eigensolver context
77: */
78: PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
80: /*
81: Set operators. In this case, it is a generalized eigenvalue problem
82: */
83: PetscCall(EPSSetOperators(eps,A,B));
84: PetscCall(EPSSetProblemType(eps,EPS_GNHEP));
86: /*
87: Set some solver options
88: */
89: PetscCall(EPSSetTarget(eps,1.3));
90: PetscCall(EPSSetDimensions(eps,2,PETSC_DEFAULT,PETSC_DEFAULT));
91: PetscCall(EPSGetST(eps,&st));
92: PetscCall(STSetType(st,STSINVERT));
94: PetscCall(STGetKSP(st,&ksp));
95: PetscCall(KSPSetType(ksp,KSPPREONLY));
96: PetscCall(KSPGetPC(ksp,&pc));
97: PetscCall(PCSetType(pc,PCLU));
99: /*
100: Set MUMPS options if available
101: */
102: #if defined(PETSC_HAVE_MUMPS)
103: PetscCall(PCFactorSetMatSolverType(pc,MATSOLVERMUMPS));
104: /* the next line is required to force the creation of the ST operator and its passing to KSP */
105: PetscCall(STGetOperator(st,NULL));
106: PetscCall(PCFactorSetUpMatSolverType(pc));
107: PetscCall(PCFactorGetMatrix(pc,&K));
108: PetscCall(MatMumpsSetIcntl(K,14,50));
109: PetscCall(MatMumpsSetCntl(K,3,1e-12));
110: #endif
112: /*
113: Let the user change settings at runtime
114: */
115: PetscCall(EPSSetFromOptions(eps));
117: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
118: Solve the eigensystem
119: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
121: PetscCall(EPSSolve(eps));
123: /*
124: Optional: Get some information from the solver and display it
125: */
126: PetscCall(EPSGetType(eps,&type));
127: PetscCall(PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type));
128: PetscCall(EPSGetDimensions(eps,&nev,NULL,NULL));
129: PetscCall(PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev));
131: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
132: Display solution and clean up
133: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
135: /* show detailed info unless -terse option is given by user */
136: PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
137: if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
138: else {
139: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
140: PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
141: PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
142: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
143: }
144: PetscCall(EPSDestroy(&eps));
145: PetscCall(MatDestroy(&A));
146: PetscCall(MatDestroy(&B));
147: PetscCall(SlepcFinalize());
148: return 0;
149: }
151: /*TEST
153: testset:
154: args: -terse
155: output_file: output/ex43_1.out
156: test:
157: suffix: 1
158: test:
159: suffix: 2
160: nsize: 2
161: args: -st_pc_factor_mat_solver_type mumps
162: requires: mumps
164: TEST*/