Line data Source code
1 : /*
2 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3 : SLEPc - Scalable Library for Eigenvalue Problem Computations
4 : Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain
5 :
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.
17 :
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 : */
23 :
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";
28 :
29 : #include <slepcpep.h>
30 :
31 11 : int main(int argc,char **argv)
32 : {
33 11 : Mat M,C,K,A[3]; /* problem matrices */
34 11 : PEP pep; /* polynomial eigenproblem solver context */
35 11 : PetscInt n=10,Istart,Iend,i;
36 11 : PetscScalar z=1.0;
37 11 : char str[50];
38 11 : PetscBool terse;
39 :
40 11 : PetscFunctionBeginUser;
41 11 : PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
42 :
43 11 : PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
44 11 : PetscCall(PetscOptionsGetScalar(NULL,NULL,"-z",&z,NULL));
45 11 : PetscCall(SlepcSNPrintfScalar(str,sizeof(str),z,PETSC_FALSE));
46 11 : PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nAcoustic wave 1-D, n=%" PetscInt_FMT " z=%s\n\n",n,str));
47 :
48 : /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
49 : Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
50 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
51 :
52 : /* K is a tridiagonal */
53 11 : PetscCall(MatCreate(PETSC_COMM_WORLD,&K));
54 11 : PetscCall(MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n));
55 11 : PetscCall(MatSetFromOptions(K));
56 :
57 11 : PetscCall(MatGetOwnershipRange(K,&Istart,&Iend));
58 275 : for (i=Istart;i<Iend;i++) {
59 264 : if (i>0) PetscCall(MatSetValue(K,i,i-1,-1.0*n,INSERT_VALUES));
60 264 : if (i<n-1) {
61 253 : PetscCall(MatSetValue(K,i,i,2.0*n,INSERT_VALUES));
62 253 : PetscCall(MatSetValue(K,i,i+1,-1.0*n,INSERT_VALUES));
63 264 : } else PetscCall(MatSetValue(K,i,i,1.0*n,INSERT_VALUES));
64 : }
65 :
66 11 : PetscCall(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY));
67 11 : PetscCall(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY));
68 :
69 : /* C is the zero matrix but one element*/
70 11 : PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
71 11 : PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n));
72 11 : PetscCall(MatSetFromOptions(C));
73 :
74 11 : PetscCall(MatGetOwnershipRange(C,&Istart,&Iend));
75 11 : if (n-1>=Istart && n-1<Iend) PetscCall(MatSetValue(C,n-1,n-1,-2*PETSC_PI/z,INSERT_VALUES));
76 11 : PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
77 11 : PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
78 :
79 : /* M is a diagonal matrix */
80 11 : PetscCall(MatCreate(PETSC_COMM_WORLD,&M));
81 11 : PetscCall(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n));
82 11 : PetscCall(MatSetFromOptions(M));
83 :
84 11 : PetscCall(MatGetOwnershipRange(M,&Istart,&Iend));
85 275 : for (i=Istart;i<Iend;i++) {
86 264 : if (i<n-1) PetscCall(MatSetValue(M,i,i,4*PETSC_PI*PETSC_PI/n,INSERT_VALUES));
87 264 : else PetscCall(MatSetValue(M,i,i,2*PETSC_PI*PETSC_PI/n,INSERT_VALUES));
88 : }
89 11 : PetscCall(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY));
90 11 : PetscCall(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY));
91 :
92 : /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
93 : Create the eigensolver and solve the problem
94 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
95 :
96 11 : PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
97 11 : A[0] = K; A[1] = C; A[2] = M;
98 11 : PetscCall(PEPSetOperators(pep,3,A));
99 11 : PetscCall(PEPSetFromOptions(pep));
100 11 : PetscCall(PEPSolve(pep));
101 :
102 : /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
103 : Display solution and clean up
104 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
105 :
106 : /* show detailed info unless -terse option is given by user */
107 11 : PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
108 11 : if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
109 : else {
110 0 : PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
111 0 : PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
112 0 : PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
113 0 : PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
114 : }
115 11 : PetscCall(PEPDestroy(&pep));
116 11 : PetscCall(MatDestroy(&M));
117 11 : PetscCall(MatDestroy(&C));
118 11 : PetscCall(MatDestroy(&K));
119 11 : PetscCall(SlepcFinalize());
120 : return 0;
121 : }
122 :
123 : /*TEST
124 :
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
144 :
145 : TEST*/
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