Actual source code: ex16.c
slepc-3.11.2 2019-07-30
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2019, 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[] = "Simple quadratic eigenvalue problem.\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]; /* problem matrices */
21: PEP pep; /* polynomial eigenproblem solver context */
22: PetscInt N,n=10,m,Istart,Iend,II,nev,i,j,nconv;
23: PetscBool flag,terse;
24: PetscReal error,re,im;
25: PetscScalar kr,ki;
26: Vec xr,xi;
29: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
31: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
32: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
33: if (!flag) m=n;
34: N = n*m;
35: PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%D (%Dx%D 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++) {
80: MatSetValue(M,II,II,(PetscReal)(II+1),INSERT_VALUES);
81: }
82: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
83: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
85: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
86: Create the eigensolver and set various options
87: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
89: /*
90: Create eigensolver context
91: */
92: PEPCreate(PETSC_COMM_WORLD,&pep);
94: /*
95: Set matrices and problem type
96: */
97: A[0] = K; A[1] = C; A[2] = M;
98: PEPSetOperators(pep,3,A);
99: PEPSetProblemType(pep,PEP_HERMITIAN);
101: /*
102: Set solver parameters at runtime
103: */
104: PEPSetFromOptions(pep);
106: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
107: Solve the eigensystem
108: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
110: PEPSolve(pep);
112: /*
113: Optional: Get some information from the solver and display it
114: */
115: PEPGetDimensions(pep,&nev,NULL,NULL);
116: PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
118: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
119: Display solution and clean up
120: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
122: /* show detailed info unless -terse option is given by user */
123: PetscOptionsHasName(NULL,NULL,"-terse",&terse);
124: if (terse) {
125: PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
126: } else {
127: PEPGetConverged(pep,&nconv);
128: if (nconv>0) {
129: MatCreateVecs(M,&xr,&xi);
130: /* display eigenvalues and relative errors */
131: PetscPrintf(PETSC_COMM_WORLD,
132: "\n k ||P(k)x||/||kx||\n"
133: " ----------------- ------------------\n");
134: for (i=0;i<nconv;i++) {
135: /* get converged eigenpairs */
136: PEPGetEigenpair(pep,i,&kr,&ki,xr,xi);
137: /* compute the relative error associated to each eigenpair */
138: PEPComputeError(pep,i,PEP_ERROR_BACKWARD,&error);
139: #if defined(PETSC_USE_COMPLEX)
140: re = PetscRealPart(kr);
141: im = PetscImaginaryPart(kr);
142: #else
143: re = kr;
144: im = ki;
145: #endif
146: if (im!=0.0) {
147: PetscPrintf(PETSC_COMM_WORLD," %9f%+9fi %12g\n",(double)re,(double)im,(double)error);
148: } else {
149: PetscPrintf(PETSC_COMM_WORLD," %12f %12g\n",(double)re,(double)error);
150: }
151: }
152: PetscPrintf(PETSC_COMM_WORLD,"\n");
153: VecDestroy(&xr);
154: VecDestroy(&xi);
155: }
156: }
157: PEPDestroy(&pep);
158: MatDestroy(&M);
159: MatDestroy(&C);
160: MatDestroy(&K);
161: SlepcFinalize();
162: return ierr;
163: }
165: /*TEST
167: testset:
168: args: -pep_nev 4 -pep_ncv 21 -n 12 -terse
169: requires: !complex
170: output_file: output/ex16_1.out
171: test:
172: suffix: 1
173: args: -pep_type {{toar qarnoldi}}
174: test:
175: suffix: 1_linear
176: args: -pep_type linear -pep_linear_explicitmatrix
177: test:
178: suffix: 1_linear_symm
179: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_eps_gen_indefinite
180: requires: !single
181: test:
182: suffix: 1_stoar
183: args: -pep_type stoar
184: requires: !single
185: test:
186: suffix: 1_stoar_t
187: args: -pep_type stoar -st_transform
188: requires: !single
190: TEST*/