Actual source code: test13.c
slepc-3.18.2 2023-01-26
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;
30: SlepcInitialize(&argc,&argv,(char*)0,help);
31: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
32: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flg);
33: if (!flg) m=n;
34: N = n*m;
35: PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);
37: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
38: Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
39: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
41: /* K is the 2-D Laplacian */
42: MatCreate(PETSC_COMM_WORLD,&K);
43: MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N);
44: MatSetFromOptions(K);
45: MatSetUp(K);
46: MatGetOwnershipRange(K,&Istart,&Iend);
47: for (II=Istart;II<Iend;II++) {
48: i = II/n; j = II-i*n;
49: if (i>0) MatSetValue(K,II,II-n,-1.0,INSERT_VALUES);
50: if (i<m-1) MatSetValue(K,II,II+n,-1.0,INSERT_VALUES);
51: if (j>0) MatSetValue(K,II,II-1,-1.0,INSERT_VALUES);
52: if (j<n-1) MatSetValue(K,II,II+1,-1.0,INSERT_VALUES);
53: MatSetValue(K,II,II,4.0,INSERT_VALUES);
54: }
55: MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
56: MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);
58: /* C is the 1-D Laplacian on horizontal lines */
59: MatCreate(PETSC_COMM_WORLD,&C);
60: MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N);
61: MatSetFromOptions(C);
62: MatSetUp(C);
63: MatGetOwnershipRange(C,&Istart,&Iend);
64: for (II=Istart;II<Iend;II++) {
65: i = II/n; j = II-i*n;
66: if (j>0) MatSetValue(C,II,II-1,-1.0,INSERT_VALUES);
67: if (j<n-1) MatSetValue(C,II,II+1,-1.0,INSERT_VALUES);
68: MatSetValue(C,II,II,2.0,INSERT_VALUES);
69: }
70: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
71: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
73: /* M is a diagonal matrix */
74: MatCreate(PETSC_COMM_WORLD,&M);
75: MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N);
76: MatSetFromOptions(M);
77: MatSetUp(M);
78: MatGetOwnershipRange(M,&Istart,&Iend);
79: for (II=Istart;II<Iend;II++) MatSetValue(M,II,II,(PetscReal)(II+1),INSERT_VALUES);
80: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
81: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
83: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
84: Create the eigensolver and solve the eigensystem
85: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
87: PEPCreate(PETSC_COMM_WORLD,&pep);
88: A[0] = K; A[1] = C; A[2] = M;
89: PEPSetOperators(pep,3,A);
90: PEPSetProblemType(pep,PEP_GENERAL);
92: /* customize polynomial eigensolver; set runtime options */
93: PEPSetType(pep,PEPCISS);
94: PEPGetRG(pep,&rg);
95: RGSetType(rg,RGELLIPSE);
96: RGEllipseSetParameters(rg,PetscCMPLX(-0.1,0.3),0.1,0.25);
97: PEPCISSSetSizes(pep,24,PETSC_DEFAULT,PETSC_DEFAULT,1,PETSC_DEFAULT,PETSC_TRUE);
98: PEPCISSGetKSPs(pep,&nsolve,&ksp);
99: for (i=0;i<nsolve;i++) {
100: KSPSetTolerances(ksp[i],1e-12,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
101: KSPSetType(ksp[i],KSPPREONLY);
102: KSPGetPC(ksp[i],&pc);
103: PCSetType(pc,PCLU);
104: }
105: PEPSetFromOptions(pep);
107: /* solve */
108: PetscObjectTypeCompare((PetscObject)pep,PEPCISS,&flg);
109: if (flg) {
110: PEPCISSGetExtraction(pep,&ext);
111: PetscPrintf(PETSC_COMM_WORLD," Running CISS with %" PetscInt_FMT " KSP solvers (%s extraction)\n",nsolve,PEPCISSExtractions[ext]);
112: }
113: PEPSolve(pep);
115: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
116: Display solution and clean up
117: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
119: PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
120: PEPDestroy(&pep);
121: MatDestroy(&M);
122: MatDestroy(&C);
123: MatDestroy(&K);
124: SlepcFinalize();
125: return 0;
126: }
128: /*TEST
130: build:
131: requires: complex
133: test:
134: suffix: 1
135: requires: complex
137: TEST*/