Actual source code: acoustic_wave_1d.c
slepc-3.21.0 2024-03-30
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_1d problem is a QEP from an acoustics application.
19: Here we solve it with the eigenvalue scaled by the imaginary unit, to be
20: able to use real arithmetic, so the computed eigenvalues should be scaled
21: back.
22: */
24: static char help[] = "Quadratic eigenproblem from an acoustics application (1-D).\n\n"
25: "The command line options are:\n"
26: " -n <n>, where <n> = dimension of the matrices.\n"
27: " -z <z>, where <z> = impedance (default 1.0).\n\n";
29: #include <slepcpep.h>
31: int main(int argc,char **argv)
32: {
33: Mat M,C,K,A[3]; /* problem matrices */
34: PEP pep; /* polynomial eigenproblem solver context */
35: PetscInt n=10,Istart,Iend,i;
36: PetscScalar z=1.0;
37: char str[50];
38: PetscBool terse;
40: PetscFunctionBeginUser;
41: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
43: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
44: PetscCall(PetscOptionsGetScalar(NULL,NULL,"-z",&z,NULL));
45: PetscCall(SlepcSNPrintfScalar(str,sizeof(str),z,PETSC_FALSE));
46: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nAcoustic wave 1-D, n=%" PetscInt_FMT " z=%s\n\n",n,str));
48: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
49: Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
50: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
52: /* K is a tridiagonal */
53: PetscCall(MatCreate(PETSC_COMM_WORLD,&K));
54: PetscCall(MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n));
55: PetscCall(MatSetFromOptions(K));
57: PetscCall(MatGetOwnershipRange(K,&Istart,&Iend));
58: for (i=Istart;i<Iend;i++) {
59: if (i>0) PetscCall(MatSetValue(K,i,i-1,-1.0*n,INSERT_VALUES));
60: if (i<n-1) {
61: PetscCall(MatSetValue(K,i,i,2.0*n,INSERT_VALUES));
62: PetscCall(MatSetValue(K,i,i+1,-1.0*n,INSERT_VALUES));
63: } else PetscCall(MatSetValue(K,i,i,1.0*n,INSERT_VALUES));
64: }
66: PetscCall(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY));
67: PetscCall(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY));
69: /* C is the zero matrix but one element*/
70: PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
71: PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n));
72: PetscCall(MatSetFromOptions(C));
74: PetscCall(MatGetOwnershipRange(C,&Istart,&Iend));
75: if (n-1>=Istart && n-1<Iend) PetscCall(MatSetValue(C,n-1,n-1,-2*PETSC_PI/z,INSERT_VALUES));
76: PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
77: PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
79: /* M is a diagonal matrix */
80: PetscCall(MatCreate(PETSC_COMM_WORLD,&M));
81: PetscCall(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n));
82: PetscCall(MatSetFromOptions(M));
84: PetscCall(MatGetOwnershipRange(M,&Istart,&Iend));
85: for (i=Istart;i<Iend;i++) {
86: if (i<n-1) PetscCall(MatSetValue(M,i,i,4*PETSC_PI*PETSC_PI/n,INSERT_VALUES));
87: else PetscCall(MatSetValue(M,i,i,2*PETSC_PI*PETSC_PI/n,INSERT_VALUES));
88: }
89: PetscCall(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY));
90: PetscCall(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY));
92: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
93: Create the eigensolver and solve the problem
94: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
96: PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
97: A[0] = K; A[1] = C; A[2] = M;
98: PetscCall(PEPSetOperators(pep,3,A));
99: PetscCall(PEPSetFromOptions(pep));
100: PetscCall(PEPSolve(pep));
102: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
103: Display solution and clean up
104: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
106: /* show detailed info unless -terse option is given by user */
107: PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
108: if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
109: else {
110: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
111: PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
112: PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
113: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
114: }
115: PetscCall(PEPDestroy(&pep));
116: PetscCall(MatDestroy(&M));
117: PetscCall(MatDestroy(&C));
118: PetscCall(MatDestroy(&K));
119: PetscCall(SlepcFinalize());
120: return 0;
121: }
123: /*TEST
125: testset:
126: args: -pep_nev 4 -pep_tol 1e-7 -n 24 -terse
127: output_file: output/acoustic_wave_1d_1.out
128: requires: !single
129: test:
130: suffix: 1
131: args: -st_type sinvert -st_transform -pep_type {{toar qarnoldi linear}}
132: test:
133: suffix: 1_stoar
134: args: -st_type sinvert -st_transform -pep_type stoar -pep_hermitian -pep_stoar_locking 0 -pep_stoar_nev 11 -pep_ncv 10
135: test:
136: suffix: 2
137: args: -st_type sinvert -st_transform -pep_type toar -pep_extract {{none norm residual}}
138: test:
139: suffix: 3
140: args: -st_type sinvert -pep_type linear -pep_extract {{none norm residual}}
141: test:
142: suffix: 4
143: args: -pep_type jd
145: TEST*/