Actual source code: test13.c
slepc-3.17.2 2022-08-09
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[] = "Solve a quadratic problem with CISS.\n\n"
12: "The command line options are:\n"
13: " -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
14: " -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";
16: #include <slepcpep.h>
18: int main(int argc,char **argv)
19: {
20: Mat M,C,K,A[3];
21: PEP pep;
22: RG rg;
23: KSP *ksp;
24: PC pc;
25: PEPCISSExtraction ext;
26: PetscInt N,n=10,m,Istart,Iend,II,i,j,nsolve;
27: PetscBool flg;
29: SlepcInitialize(&argc,&argv,(char*)0,help);
30: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
31: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flg);
32: if (!flg) m=n;
33: N = n*m;
34: PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);
36: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
37: Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
38: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
40: /* K is the 2-D Laplacian */
41: MatCreate(PETSC_COMM_WORLD,&K);
42: MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N);
43: MatSetFromOptions(K);
44: MatSetUp(K);
45: MatGetOwnershipRange(K,&Istart,&Iend);
46: for (II=Istart;II<Iend;II++) {
47: i = II/n; j = II-i*n;
48: if (i>0) MatSetValue(K,II,II-n,-1.0,INSERT_VALUES);
49: if (i<m-1) MatSetValue(K,II,II+n,-1.0,INSERT_VALUES);
50: if (j>0) MatSetValue(K,II,II-1,-1.0,INSERT_VALUES);
51: if (j<n-1) MatSetValue(K,II,II+1,-1.0,INSERT_VALUES);
52: MatSetValue(K,II,II,4.0,INSERT_VALUES);
53: }
54: MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
55: MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);
57: /* C is the 1-D Laplacian on horizontal lines */
58: MatCreate(PETSC_COMM_WORLD,&C);
59: MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N);
60: MatSetFromOptions(C);
61: MatSetUp(C);
62: MatGetOwnershipRange(C,&Istart,&Iend);
63: for (II=Istart;II<Iend;II++) {
64: i = II/n; j = II-i*n;
65: if (j>0) MatSetValue(C,II,II-1,-1.0,INSERT_VALUES);
66: if (j<n-1) MatSetValue(C,II,II+1,-1.0,INSERT_VALUES);
67: MatSetValue(C,II,II,2.0,INSERT_VALUES);
68: }
69: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
70: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
72: /* M is a diagonal matrix */
73: MatCreate(PETSC_COMM_WORLD,&M);
74: MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N);
75: MatSetFromOptions(M);
76: MatSetUp(M);
77: MatGetOwnershipRange(M,&Istart,&Iend);
78: for (II=Istart;II<Iend;II++) MatSetValue(M,II,II,(PetscReal)(II+1),INSERT_VALUES);
79: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
80: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
82: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
83: Create the eigensolver and solve the eigensystem
84: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
86: PEPCreate(PETSC_COMM_WORLD,&pep);
87: A[0] = K; A[1] = C; A[2] = M;
88: PEPSetOperators(pep,3,A);
89: PEPSetProblemType(pep,PEP_GENERAL);
91: /* customize polynomial eigensolver; set runtime options */
92: PEPSetType(pep,PEPCISS);
93: PEPGetRG(pep,&rg);
94: RGSetType(rg,RGELLIPSE);
95: RGEllipseSetParameters(rg,PetscCMPLX(-0.1,0.3),0.1,0.25);
96: PEPCISSSetSizes(pep,24,PETSC_DEFAULT,PETSC_DEFAULT,1,PETSC_DEFAULT,PETSC_TRUE);
97: PEPCISSGetKSPs(pep,&nsolve,&ksp);
98: for (i=0;i<nsolve;i++) {
99: KSPSetTolerances(ksp[i],1e-12,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
100: KSPSetType(ksp[i],KSPPREONLY);
101: KSPGetPC(ksp[i],&pc);
102: PCSetType(pc,PCLU);
103: }
104: PEPSetFromOptions(pep);
106: /* solve */
107: PetscObjectTypeCompare((PetscObject)pep,PEPCISS,&flg);
108: if (flg) {
109: PEPCISSGetExtraction(pep,&ext);
110: PetscPrintf(PETSC_COMM_WORLD," Running CISS with %" PetscInt_FMT " KSP solvers (%s extraction)\n",nsolve,PEPCISSExtractions[ext]);
111: }
112: PEPSolve(pep);
114: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
115: Display solution and clean up
116: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
118: PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
119: PEPDestroy(&pep);
120: MatDestroy(&M);
121: MatDestroy(&C);
122: MatDestroy(&K);
123: SlepcFinalize();
124: return 0;
125: }
127: /*TEST
129: build:
130: requires: complex
132: test:
133: suffix: 1
134: requires: complex
136: TEST*/