Actual source code: wiresaw.c
slepc-3.17.1 2022-04-11
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 two 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: WIRESAW1 is a gyroscopic QEP from vibration analysis of a wiresaw,
19: where the parameter V represents the speed of the wire. When the
20: parameter eta is nonzero, then it turns into the WIRESAW2 problem
21: (with added viscous damping, e.g. eta=0.8).
23: [2] S. Wei and I. Kao, "Vibration analysis of wire and frequency
24: response in the modern wiresaw manufacturing process", J. Sound
25: Vib. 213(5):1383-1395, 2000.
26: */
28: static char help[] = "Vibration analysis of a wiresaw.\n\n"
29: "The command line options are:\n"
30: " -n <n> ... dimension of the matrices (default 10).\n"
31: " -v <value> ... velocity of the wire (default 0.01).\n"
32: " -eta <value> ... viscous damping (default 0.0).\n\n";
34: #include <slepcpep.h>
36: int main(int argc,char **argv)
37: {
38: Mat M,D,K,A[3]; /* problem matrices */
39: PEP pep; /* polynomial eigenproblem solver context */
40: PetscInt n=10,Istart,Iend,j,k;
41: PetscReal v=0.01,eta=0.0;
42: PetscBool terse;
44: SlepcInitialize(&argc,&argv,(char*)0,help);
46: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
47: PetscOptionsGetReal(NULL,NULL,"-v",&v,NULL);
48: PetscOptionsGetReal(NULL,NULL,"-eta",&eta,NULL);
49: PetscPrintf(PETSC_COMM_WORLD,"\nVibration analysis of a wiresaw, n=%" PetscInt_FMT " v=%g eta=%g\n\n",n,(double)v,(double)eta);
51: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
52: Compute the matrices that define the eigensystem, (k^2*M+k*D+K)x=0
53: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
55: /* K is a diagonal matrix */
56: MatCreate(PETSC_COMM_WORLD,&K);
57: MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
58: MatSetFromOptions(K);
59: MatSetUp(K);
61: MatGetOwnershipRange(K,&Istart,&Iend);
62: for (j=Istart;j<Iend;j++) MatSetValue(K,j,j,(j+1)*(j+1)*PETSC_PI*PETSC_PI*(1.0-v*v),INSERT_VALUES);
64: MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
65: MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);
66: MatScale(K,0.5);
68: /* D is a tridiagonal */
69: MatCreate(PETSC_COMM_WORLD,&D);
70: MatSetSizes(D,PETSC_DECIDE,PETSC_DECIDE,n,n);
71: MatSetFromOptions(D);
72: MatSetUp(D);
74: MatGetOwnershipRange(D,&Istart,&Iend);
75: for (j=Istart;j<Iend;j++) {
76: for (k=0;k<n;k++) {
77: if ((j+k)%2) MatSetValue(D,j,k,8.0*(j+1)*(k+1)*v/((j+1)*(j+1)-(k+1)*(k+1)),INSERT_VALUES);
78: }
79: }
81: MatAssemblyBegin(D,MAT_FINAL_ASSEMBLY);
82: MatAssemblyEnd(D,MAT_FINAL_ASSEMBLY);
83: MatScale(D,0.5);
85: /* M is a diagonal matrix */
86: MatCreate(PETSC_COMM_WORLD,&M);
87: MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
88: MatSetFromOptions(M);
89: MatSetUp(M);
90: MatGetOwnershipRange(M,&Istart,&Iend);
91: for (j=Istart;j<Iend;j++) MatSetValue(M,j,j,1.0,INSERT_VALUES);
92: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
93: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
94: MatScale(M,0.5);
96: /* add damping */
97: if (eta>0.0) {
98: MatAXPY(K,eta,D,DIFFERENT_NONZERO_PATTERN); /* K = K + eta*D */
99: MatShift(D,eta); /* D = D + eta*eye(n) */
100: }
102: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
103: Create the eigensolver and solve the problem
104: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
106: PEPCreate(PETSC_COMM_WORLD,&pep);
107: A[0] = K; A[1] = D; A[2] = M;
108: PEPSetOperators(pep,3,A);
109: if (eta==0.0) PEPSetProblemType(pep,PEP_GYROSCOPIC);
110: else PEPSetProblemType(pep,PEP_GENERAL);
111: PEPSetFromOptions(pep);
112: PEPSolve(pep);
114: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
115: Display solution and clean up
116: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
118: /* show detailed info unless -terse option is given by user */
119: PetscOptionsHasName(NULL,NULL,"-terse",&terse);
120: if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
121: else {
122: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
123: PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
124: PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
125: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
126: }
127: PEPDestroy(&pep);
128: MatDestroy(&M);
129: MatDestroy(&D);
130: MatDestroy(&K);
131: SlepcFinalize();
132: return 0;
133: }
135: /*TEST
137: testset:
138: args: -pep_nev 4 -terse
139: requires: double
140: output_file: output/wiresaw_1.out
141: test:
142: suffix: 1
143: args: -pep_type {{toar qarnoldi}}
144: test:
145: suffix: 1_linear_h1
146: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_linearization 1,0 -pep_linear_st_ksp_type bcgs -pep_linear_st_pc_type kaczmarz
147: test:
148: suffix: 1_linear_h2
149: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_linearization 0,1
151: TEST*/