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 damped_beam problem is a QEP from the vibrarion analysis of a beam
19 : simply supported at both ends and damped in the middle.
20 : */
21 :
22 : static char help[] = "Quadratic eigenproblem from the vibrarion analysis of a beam.\n\n"
23 : "The command line options are:\n"
24 : " -n <n> ... dimension of the matrices.\n\n";
25 :
26 : #include <slepcpep.h>
27 :
28 8 : int main(int argc,char **argv)
29 : {
30 8 : Mat M,Mo,C,K,Ko,A[3]; /* problem matrices */
31 8 : PEP pep; /* polynomial eigenproblem solver context */
32 8 : IS isf,isbc,is;
33 8 : PetscInt n=200,nele,Istart,Iend,i,j,mloc,nloc,bc[2];
34 8 : PetscReal width=0.05,height=0.005,glength=1.0,dlen,EI,area,rho;
35 8 : PetscScalar K1[4],K2[4],K2t[4],K3[4],M1[4],M2[4],M2t[4],M3[4],damp=5.0;
36 8 : PetscBool terse;
37 :
38 8 : PetscFunctionBeginUser;
39 8 : PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
40 :
41 8 : PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
42 8 : nele = n/2;
43 8 : n = 2*nele;
44 8 : PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nSimply supported beam damped in the middle, n=%" PetscInt_FMT " (nele=%" PetscInt_FMT ")\n\n",n,nele));
45 :
46 8 : dlen = glength/nele;
47 8 : EI = 7e10*width*height*height*height/12.0;
48 8 : area = width*height;
49 8 : rho = 0.674/(area*glength);
50 :
51 8 : K1[0] = 12; K1[1] = 6*dlen; K1[2] = 6*dlen; K1[3] = 4*dlen*dlen;
52 8 : K2[0] = -12; K2[1] = 6*dlen; K2[2] = -6*dlen; K2[3] = 2*dlen*dlen;
53 8 : K2t[0] = -12; K2t[1] = -6*dlen; K2t[2] = 6*dlen; K2t[3] = 2*dlen*dlen;
54 8 : K3[0] = 12; K3[1] = -6*dlen; K3[2] = -6*dlen; K3[3] = 4*dlen*dlen;
55 8 : M1[0] = 156; M1[1] = 22*dlen; M1[2] = 22*dlen; M1[3] = 4*dlen*dlen;
56 8 : M2[0] = 54; M2[1] = -13*dlen; M2[2] = 13*dlen; M2[3] = -3*dlen*dlen;
57 8 : M2t[0] = 54; M2t[1] = 13*dlen; M2t[2] = -13*dlen; M2t[3] = -3*dlen*dlen;
58 8 : M3[0] = 156; M3[1] = -22*dlen; M3[2] = -22*dlen; M3[3] = 4*dlen*dlen;
59 :
60 : /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
61 : Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
62 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
63 :
64 : /* K is block-tridiagonal */
65 8 : PetscCall(MatCreate(PETSC_COMM_WORLD,&Ko));
66 8 : PetscCall(MatSetSizes(Ko,PETSC_DECIDE,PETSC_DECIDE,n+2,n+2));
67 8 : PetscCall(MatSetBlockSize(Ko,2));
68 8 : PetscCall(MatSetFromOptions(Ko));
69 :
70 8 : PetscCall(MatGetOwnershipRange(Ko,&Istart,&Iend));
71 816 : for (i=Istart/2;i<Iend/2;i++) {
72 808 : if (i>0) {
73 800 : j = i-1;
74 800 : PetscCall(MatSetValuesBlocked(Ko,1,&i,1,&j,K2t,ADD_VALUES));
75 800 : PetscCall(MatSetValuesBlocked(Ko,1,&i,1,&i,K3,ADD_VALUES));
76 : }
77 808 : if (i<nele) {
78 800 : j = i+1;
79 800 : PetscCall(MatSetValuesBlocked(Ko,1,&i,1,&j,K2,ADD_VALUES));
80 808 : PetscCall(MatSetValuesBlocked(Ko,1,&i,1,&i,K1,ADD_VALUES));
81 : }
82 : }
83 8 : PetscCall(MatAssemblyBegin(Ko,MAT_FINAL_ASSEMBLY));
84 8 : PetscCall(MatAssemblyEnd(Ko,MAT_FINAL_ASSEMBLY));
85 8 : PetscCall(MatScale(Ko,EI/(dlen*dlen*dlen)));
86 :
87 : /* M is block-tridiagonal */
88 8 : PetscCall(MatCreate(PETSC_COMM_WORLD,&Mo));
89 8 : PetscCall(MatSetSizes(Mo,PETSC_DECIDE,PETSC_DECIDE,n+2,n+2));
90 8 : PetscCall(MatSetBlockSize(Mo,2));
91 8 : PetscCall(MatSetFromOptions(Mo));
92 :
93 8 : PetscCall(MatGetOwnershipRange(Mo,&Istart,&Iend));
94 816 : for (i=Istart/2;i<Iend/2;i++) {
95 808 : if (i>0) {
96 800 : j = i-1;
97 800 : PetscCall(MatSetValuesBlocked(Mo,1,&i,1,&j,M2t,ADD_VALUES));
98 800 : PetscCall(MatSetValuesBlocked(Mo,1,&i,1,&i,M3,ADD_VALUES));
99 : }
100 808 : if (i<nele) {
101 800 : j = i+1;
102 800 : PetscCall(MatSetValuesBlocked(Mo,1,&i,1,&j,M2,ADD_VALUES));
103 808 : PetscCall(MatSetValuesBlocked(Mo,1,&i,1,&i,M1,ADD_VALUES));
104 : }
105 : }
106 8 : PetscCall(MatAssemblyBegin(Mo,MAT_FINAL_ASSEMBLY));
107 8 : PetscCall(MatAssemblyEnd(Mo,MAT_FINAL_ASSEMBLY));
108 8 : PetscCall(MatScale(Mo,rho*area*dlen/420));
109 :
110 : /* remove rows/columns from K and M corresponding to boundary conditions */
111 8 : PetscCall(ISCreateStride(PETSC_COMM_WORLD,Iend-Istart,Istart,1,&isf));
112 8 : bc[0] = 0; bc[1] = n;
113 8 : PetscCall(ISCreateGeneral(PETSC_COMM_SELF,2,bc,PETSC_USE_POINTER,&isbc));
114 8 : PetscCall(ISDifference(isf,isbc,&is));
115 8 : PetscCall(MatCreateSubMatrix(Ko,is,is,MAT_INITIAL_MATRIX,&K));
116 8 : PetscCall(MatCreateSubMatrix(Mo,is,is,MAT_INITIAL_MATRIX,&M));
117 8 : PetscCall(MatGetLocalSize(M,&mloc,&nloc));
118 :
119 : /* C is zero except for the (nele,nele)-entry */
120 8 : PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
121 8 : PetscCall(MatSetSizes(C,mloc,nloc,PETSC_DECIDE,PETSC_DECIDE));
122 8 : PetscCall(MatSetFromOptions(C));
123 :
124 8 : PetscCall(MatGetOwnershipRange(C,&Istart,&Iend));
125 8 : if (nele-1>=Istart && nele-1<Iend) PetscCall(MatSetValue(C,nele-1,nele-1,damp,INSERT_VALUES));
126 8 : PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
127 8 : PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
128 :
129 : /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
130 : Create the eigensolver and solve the problem
131 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
132 :
133 8 : PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
134 8 : A[0] = K; A[1] = C; A[2] = M;
135 8 : PetscCall(PEPSetOperators(pep,3,A));
136 8 : PetscCall(PEPSetFromOptions(pep));
137 8 : PetscCall(PEPSolve(pep));
138 :
139 : /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
140 : Display solution and clean up
141 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
142 :
143 : /* show detailed info unless -terse option is given by user */
144 8 : PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
145 8 : if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
146 : else {
147 0 : PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
148 0 : PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
149 0 : PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
150 0 : PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
151 : }
152 8 : PetscCall(PEPDestroy(&pep));
153 8 : PetscCall(ISDestroy(&isf));
154 8 : PetscCall(ISDestroy(&isbc));
155 8 : PetscCall(ISDestroy(&is));
156 8 : PetscCall(MatDestroy(&M));
157 8 : PetscCall(MatDestroy(&C));
158 8 : PetscCall(MatDestroy(&K));
159 8 : PetscCall(MatDestroy(&Ko));
160 8 : PetscCall(MatDestroy(&Mo));
161 8 : PetscCall(SlepcFinalize());
162 : return 0;
163 : }
164 :
165 : /*TEST
166 :
167 : testset:
168 : args: -pep_nev 2 -pep_ncv 12 -pep_target 0 -terse
169 : requires: !single
170 : output_file: output/damped_beam_1.out
171 : test:
172 : suffix: 1
173 : args: -pep_type {{toar linear}} -st_type sinvert
174 : test:
175 : suffix: 1_qarnoldi
176 : args: -pep_type qarnoldi -pep_qarnoldi_locking 0 -st_type sinvert
177 : test:
178 : suffix: 1_jd
179 : args: -pep_type jd
180 : filter: sed -e "s/23066i/23065i/"
181 :
182 : testset:
183 : args: -pep_nev 2 -pep_ncv 12 -pep_target 1i -terse
184 : requires: complex !single
185 : output_file: output/damped_beam_1.out
186 : test:
187 : suffix: 1_complex
188 : args: -pep_type {{toar linear}} -st_type sinvert
189 : test:
190 : suffix: 1_qarnoldi_complex
191 : args: -pep_type qarnoldi -pep_qarnoldi_locking 0 -st_type sinvert
192 : test:
193 : suffix: 1_jd_complex
194 : args: -pep_type jd
195 :
196 : TEST*/
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