Actual source code: acoustic_wave_2d.c

slepc-3.20.1 2023-11-27
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```  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,(char*)0,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));
58:   PetscCall(MatSetUp(K));

60:   PetscCall(MatGetOwnershipRange(K,&Istart,&Iend));
61:   for (II=Istart;II<Iend;II++) {
62:     i = II/m; j = II-i*m;
63:     if (i>0) PetscCall(MatSetValue(K,II,II-m,(j==m-1)?-0.5:-1.0,INSERT_VALUES));
64:     if (i<m-2) PetscCall(MatSetValue(K,II,II+m,(j==m-1)?-0.5:-1.0,INSERT_VALUES));
65:     if (j>0) PetscCall(MatSetValue(K,II,II-1,-1.0,INSERT_VALUES));
66:     if (j<m-1) PetscCall(MatSetValue(K,II,II+1,-1.0,INSERT_VALUES));
67:     PetscCall(MatSetValue(K,II,II,(j==m-1)?2.0:4.0,INSERT_VALUES));
68:   }

70:   PetscCall(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY));
71:   PetscCall(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY));

73:   /* C is the zero matrix except for a few nonzero elements on the diagonal */
74:   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
75:   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n));
76:   PetscCall(MatSetFromOptions(C));
77:   PetscCall(MatSetUp(C));

79:   PetscCall(MatGetOwnershipRange(C,&Istart,&Iend));
80:   for (i=Istart;i<Iend;i++) {
81:     if (i%m==m-1) PetscCall(MatSetValue(C,i,i,-2*PETSC_PI*h/z,INSERT_VALUES));
82:   }
83:   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
84:   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));

86:   /* M is a diagonal matrix */
87:   PetscCall(MatCreate(PETSC_COMM_WORLD,&M));
88:   PetscCall(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n));
89:   PetscCall(MatSetFromOptions(M));
90:   PetscCall(MatSetUp(M));

92:   PetscCall(MatGetOwnershipRange(M,&Istart,&Iend));
93:   for (i=Istart;i<Iend;i++) {
94:     if (i%m==m-1) PetscCall(MatSetValue(M,i,i,2*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES));
95:     else PetscCall(MatSetValue(M,i,i,4*PETSC_PI*PETSC_PI*h*h,INSERT_VALUES));
96:   }
97:   PetscCall(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY));
98:   PetscCall(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY));

100:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
101:                 Create the eigensolver and solve the problem
102:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

104:   PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
105:   A[0] = K; A[1] = C; A[2] = M;
106:   PetscCall(PEPSetOperators(pep,3,A));
107:   PetscCall(PEPSetFromOptions(pep));
108:   PetscCall(PEPSolve(pep));

110:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
111:                     Display solution and clean up
112:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

114:   /* show detailed info unless -terse option is given by user */
115:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
116:   if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
117:   else {
118:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
119:     PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
120:     PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
121:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
122:   }
123:   PetscCall(PEPDestroy(&pep));
124:   PetscCall(MatDestroy(&M));
125:   PetscCall(MatDestroy(&C));
126:   PetscCall(MatDestroy(&K));
127:   PetscCall(SlepcFinalize());
128:   return 0;
129: }

131: /*TEST

133:    testset:
134:       args: -pep_nev 2 -pep_ncv 18 -terse
135:       output_file: output/acoustic_wave_2d_1.out
136:       filter: sed -e "s/2.60936i/2.60937i/g" | sed -e "s/2.60938i/2.60937i/g"
137:       test:
138:          suffix: 1
139:          args: -pep_type {{qarnoldi linear}}
140:       test:
141:          suffix: 1_toar
142:          args: -pep_type toar -pep_toar_locking 0

144:    testset:
145:       args: -pep_nev 2 -pep_ncv 18 -pep_type stoar -pep_hermitian -pep_scale scalar -st_type sinvert -terse
146:       output_file: output/acoustic_wave_2d_2.out
147:       test:
148:          suffix: 2
149:       test:
150:          suffix: 2_lin_b
151:          args: -pep_stoar_linearization 0,1
152:       test:
153:          suffix: 2_lin_ab
154:          args: -pep_stoar_linearization 0.1,0.9

156: TEST*/
```