Actual source code: wiresaw.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 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: PetscFunctionBeginUser;
45: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
47: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
48: PetscCall(PetscOptionsGetReal(NULL,NULL,"-v",&v,NULL));
49: PetscCall(PetscOptionsGetReal(NULL,NULL,"-eta",&eta,NULL));
50: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nVibration analysis of a wiresaw, n=%" PetscInt_FMT " v=%g eta=%g\n\n",n,(double)v,(double)eta));
52: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
53: Compute the matrices that define the eigensystem, (k^2*M+k*D+K)x=0
54: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
56: /* K is a diagonal matrix */
57: PetscCall(MatCreate(PETSC_COMM_WORLD,&K));
58: PetscCall(MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n));
59: PetscCall(MatSetFromOptions(K));
61: PetscCall(MatGetOwnershipRange(K,&Istart,&Iend));
62: for (j=Istart;j<Iend;j++) PetscCall(MatSetValue(K,j,j,(j+1)*(j+1)*PETSC_PI*PETSC_PI*(1.0-v*v),INSERT_VALUES));
64: PetscCall(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY));
65: PetscCall(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY));
66: PetscCall(MatScale(K,0.5));
68: /* D is a tridiagonal */
69: PetscCall(MatCreate(PETSC_COMM_WORLD,&D));
70: PetscCall(MatSetSizes(D,PETSC_DECIDE,PETSC_DECIDE,n,n));
71: PetscCall(MatSetFromOptions(D));
73: PetscCall(MatGetOwnershipRange(D,&Istart,&Iend));
74: for (j=Istart;j<Iend;j++) {
75: for (k=0;k<n;k++) {
76: if ((j+k)%2) PetscCall(MatSetValue(D,j,k,8.0*(j+1)*(k+1)*v/((j+1)*(j+1)-(k+1)*(k+1)),INSERT_VALUES));
77: }
78: }
80: PetscCall(MatAssemblyBegin(D,MAT_FINAL_ASSEMBLY));
81: PetscCall(MatAssemblyEnd(D,MAT_FINAL_ASSEMBLY));
82: PetscCall(MatScale(D,0.5));
84: /* M is a diagonal matrix */
85: PetscCall(MatCreate(PETSC_COMM_WORLD,&M));
86: PetscCall(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n));
87: PetscCall(MatSetFromOptions(M));
88: PetscCall(MatGetOwnershipRange(M,&Istart,&Iend));
89: for (j=Istart;j<Iend;j++) PetscCall(MatSetValue(M,j,j,1.0,INSERT_VALUES));
90: PetscCall(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY));
91: PetscCall(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY));
92: PetscCall(MatScale(M,0.5));
94: /* add damping */
95: if (eta>0.0) {
96: PetscCall(MatAXPY(K,eta,D,DIFFERENT_NONZERO_PATTERN)); /* K = K + eta*D */
97: PetscCall(MatShift(D,eta)); /* D = D + eta*eye(n) */
98: }
100: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
101: Create the eigensolver and solve the problem
102: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
104: PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
105: A[0] = K; A[1] = D; A[2] = M;
106: PetscCall(PEPSetOperators(pep,3,A));
107: if (eta==0.0) PetscCall(PEPSetProblemType(pep,PEP_GYROSCOPIC));
108: else PetscCall(PEPSetProblemType(pep,PEP_GENERAL));
109: PetscCall(PEPSetFromOptions(pep));
110: PetscCall(PEPSolve(pep));
112: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
113: Display solution and clean up
114: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
116: /* show detailed info unless -terse option is given by user */
117: PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
118: if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
119: else {
120: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
121: PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
122: PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
123: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
124: }
125: PetscCall(PEPDestroy(&pep));
126: PetscCall(MatDestroy(&M));
127: PetscCall(MatDestroy(&D));
128: PetscCall(MatDestroy(&K));
129: PetscCall(SlepcFinalize());
130: return 0;
131: }
133: /*TEST
135: testset:
136: args: -pep_nev 4 -terse
137: requires: double
138: output_file: output/wiresaw_1.out
139: test:
140: suffix: 1
141: args: -pep_type {{toar qarnoldi}}
142: test:
143: suffix: 1_linear_h1
144: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_linearization 1,0 -pep_linear_st_ksp_type bcgs -pep_linear_st_pc_type kaczmarz
145: test:
146: suffix: 1_linear_h2
147: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_linearization 0,1
149: TEST*/