Actual source code: acoustic_wave_2d.c
slepc-3.16.1 2021-11-17
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2021, 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: */
10: /*
11: This example implements one of the problems found at
12: NLEVP: A Collection of Nonlinear Eigenvalue Problems,
13: The University of Manchester.
14: The details of the collection can be found at:
15: [1] T. Betcke et al., "NLEVP: A Collection of Nonlinear Eigenvalue
16: Problems", ACM Trans. Math. Software 39(2), Article 7, 2013.
18: The acoustic_wave_2d problem is a 2-D version of acoustic_wave_1d, also
19: scaled for real arithmetic.
20: */
22: static char help[] = "Quadratic eigenproblem from an acoustics application (2-D).\n\n"
23: "The command line options are:\n"
24: " -m <m>, where <m> = grid size, the matrices have dimension m*(m-1).\n"
25: " -z <z>, where <z> = impedance (default 1.0).\n\n";
27: #include <slepcpep.h>
29: int main(int argc,char **argv)
30: {
31: Mat M,C,K,A[3]; /* problem matrices */
32: PEP pep; /* polynomial eigenproblem solver context */
33: PetscInt m=6,n,II,Istart,Iend,i,j;
34: PetscScalar z=1.0;
35: PetscReal h;
36: char str[50];
37: PetscBool terse;
40: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
42: PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
43: if (m<2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"m must be at least 2");
44: PetscOptionsGetScalar(NULL,NULL,"-z",&z,NULL);
45: h = 1.0/m;
46: n = m*(m-1);
47: SlepcSNPrintfScalar(str,sizeof(str),z,PETSC_FALSE);
48: PetscPrintf(PETSC_COMM_WORLD,"\nAcoustic wave 2-D, n=%D (m=%D), z=%s\n\n",n,m,str);
50: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
51: Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
52: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
54: /* K has a pattern similar to the 2D Laplacian */
55: MatCreate(PETSC_COMM_WORLD,&K);
56: MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
57: MatSetFromOptions(K);
58: MatSetUp(K);
60: MatGetOwnershipRange(K,&Istart,&Iend);
61: for (II=Istart;II<Iend;II++) {
62: i = II/m; j = II-i*m;
63: if (i>0) { MatSetValue(K,II,II-m,(j==m-1)?-0.5:-1.0,INSERT_VALUES); }
64: if (i<m-2) { MatSetValue(K,II,II+m,(j==m-1)?-0.5:-1.0,INSERT_VALUES); }
65: if (j>0) { MatSetValue(K,II,II-1,-1.0,INSERT_VALUES); }
66: if (j<m-1) { MatSetValue(K,II,II+1,-1.0,INSERT_VALUES); }
67: MatSetValue(K,II,II,(j==m-1)?2.0:4.0,INSERT_VALUES);
68: }
70: MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
71: MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);
73: /* C is the zero matrix except for a few nonzero elements on the diagonal */
74: MatCreate(PETSC_COMM_WORLD,&C);
75: MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
76: MatSetFromOptions(C);
77: MatSetUp(C);
79: MatGetOwnershipRange(C,&Istart,&Iend);
80: for (i=Istart;i<Iend;i++) {
81: if (i%m==m-1) {
82: MatSetValue(C,i,i,-2*PETSC_PI*h/z,INSERT_VALUES);
83: }
84: }
85: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
86: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
88: /* M is a diagonal matrix */
89: MatCreate(PETSC_COMM_WORLD,&M);
90: MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
91: MatSetFromOptions(M);
92: MatSetUp(M);
94: MatGetOwnershipRange(M,&Istart,&Iend);
95: for (i=Istart;i<Iend;i++) {
96: if (i%m==m-1) {
97: MatSetValue(M,i,i,2*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES);
98: } else {
99: MatSetValue(M,i,i,4*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES);
100: }
101: }
102: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
103: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
105: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
106: Create the eigensolver and solve the problem
107: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
109: PEPCreate(PETSC_COMM_WORLD,&pep);
110: A[0] = K; A[1] = C; A[2] = M;
111: PEPSetOperators(pep,3,A);
112: PEPSetFromOptions(pep);
113: PEPSolve(pep);
115: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
116: Display solution and clean up
117: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
119: /* show detailed info unless -terse option is given by user */
120: PetscOptionsHasName(NULL,NULL,"-terse",&terse);
121: if (terse) {
122: PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
123: } else {
124: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
125: PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
126: PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
127: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
128: }
129: PEPDestroy(&pep);
130: MatDestroy(&M);
131: MatDestroy(&C);
132: MatDestroy(&K);
133: SlepcFinalize();
134: return ierr;
135: }
137: /*TEST
139: testset:
140: args: -pep_nev 2 -pep_ncv 18 -terse
141: output_file: output/acoustic_wave_2d_1.out
142: filter: sed -e "s/2.60936i/2.60937i/g" | sed -e "s/2.60938i/2.60937i/g"
143: test:
144: suffix: 1
145: args: -pep_type {{qarnoldi linear}}
146: test:
147: suffix: 1_toar
148: args: -pep_type toar -pep_toar_locking 0
150: test:
151: suffix: 2
152: args: -pep_nev 2 -pep_ncv 18 -pep_type stoar -pep_hermitian -pep_scale scalar -st_type sinvert -terse
154: TEST*/