Actual source code: acoustic_wave_2d.c
slepc-3.23.1 2025-05-01
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: */
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;
39: PetscFunctionBeginUser;
40: PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
42: PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
43: PetscCheck(m>1,PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"m must be at least 2");
44: PetscCall(PetscOptionsGetScalar(NULL,NULL,"-z",&z,NULL));
45: h = 1.0/m;
46: n = m*(m-1);
47: PetscCall(SlepcSNPrintfScalar(str,sizeof(str),z,PETSC_FALSE));
48: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nAcoustic wave 2-D, n=%" PetscInt_FMT " (m=%" PetscInt_FMT "), 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: PetscCall(MatCreate(PETSC_COMM_WORLD,&K));
56: PetscCall(MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n));
57: PetscCall(MatSetFromOptions(K));
59: PetscCall(MatGetOwnershipRange(K,&Istart,&Iend));
60: for (II=Istart;II<Iend;II++) {
61: i = II/m; j = II-i*m;
62: if (i>0) PetscCall(MatSetValue(K,II,II-m,(j==m-1)?-0.5:-1.0,INSERT_VALUES));
63: if (i<m-2) PetscCall(MatSetValue(K,II,II+m,(j==m-1)?-0.5:-1.0,INSERT_VALUES));
64: if (j>0) PetscCall(MatSetValue(K,II,II-1,-1.0,INSERT_VALUES));
65: if (j<m-1) PetscCall(MatSetValue(K,II,II+1,-1.0,INSERT_VALUES));
66: PetscCall(MatSetValue(K,II,II,(j==m-1)?2.0:4.0,INSERT_VALUES));
67: }
69: PetscCall(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY));
70: PetscCall(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY));
72: /* C is the zero matrix except for a few nonzero elements on the diagonal */
73: PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
74: PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n));
75: PetscCall(MatSetFromOptions(C));
77: PetscCall(MatGetOwnershipRange(C,&Istart,&Iend));
78: for (i=Istart;i<Iend;i++) {
79: if (i%m==m-1) PetscCall(MatSetValue(C,i,i,-2*PETSC_PI*h/z,INSERT_VALUES));
80: }
81: PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
82: PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
84: /* M is a diagonal matrix */
85: PetscCall(MatCreate(PETSC_COMM_WORLD,&M));
86: PetscCall(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n));
87: PetscCall(MatSetFromOptions(M));
89: PetscCall(MatGetOwnershipRange(M,&Istart,&Iend));
90: for (i=Istart;i<Iend;i++) {
91: if (i%m==m-1) PetscCall(MatSetValue(M,i,i,2*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES));
92: else PetscCall(MatSetValue(M,i,i,4*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES));
93: }
94: PetscCall(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY));
95: PetscCall(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY));
97: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
98: Create the eigensolver and solve the problem
99: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
101: PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
102: A[0] = K; A[1] = C; A[2] = M;
103: PetscCall(PEPSetOperators(pep,3,A));
104: PetscCall(PEPSetFromOptions(pep));
105: PetscCall(PEPSolve(pep));
107: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
108: Display solution and clean up
109: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
111: /* show detailed info unless -terse option is given by user */
112: PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
113: if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
114: else {
115: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
116: PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
117: PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
118: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
119: }
120: PetscCall(PEPDestroy(&pep));
121: PetscCall(MatDestroy(&M));
122: PetscCall(MatDestroy(&C));
123: PetscCall(MatDestroy(&K));
124: PetscCall(SlepcFinalize());
125: return 0;
126: }
128: /*TEST
130: testset:
131: args: -pep_nev 2 -pep_ncv 18 -terse
132: output_file: output/acoustic_wave_2d_1.out
133: filter: sed -e "s/2.60936i/2.60937i/g" | sed -e "s/2.60938i/2.60937i/g"
134: test:
135: suffix: 1
136: args: -pep_type {{qarnoldi linear}}
137: test:
138: suffix: 1_toar
139: args: -pep_type toar -pep_toar_locking 0
141: testset:
142: args: -pep_nev 2 -pep_ncv 18 -pep_type stoar -pep_hermitian -pep_scale scalar -st_type sinvert -terse
143: output_file: output/acoustic_wave_2d_2.out
144: test:
145: suffix: 2
146: test:
147: suffix: 2_lin_b
148: args: -pep_stoar_linearization 0,1
149: test:
150: suffix: 2_lin_ab
151: args: -pep_stoar_linearization 0.1,0.9
153: TEST*/