Actual source code: wiresaw.c
slepc-3.18.0 2022-10-01
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;
45: SlepcInitialize(&argc,&argv,(char*)0,help);
47: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
48: PetscOptionsGetReal(NULL,NULL,"-v",&v,NULL);
49: PetscOptionsGetReal(NULL,NULL,"-eta",&eta,NULL);
50: 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: MatCreate(PETSC_COMM_WORLD,&K);
58: MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
59: MatSetFromOptions(K);
60: MatSetUp(K);
62: MatGetOwnershipRange(K,&Istart,&Iend);
63: for (j=Istart;j<Iend;j++) MatSetValue(K,j,j,(j+1)*(j+1)*PETSC_PI*PETSC_PI*(1.0-v*v),INSERT_VALUES);
65: MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
66: MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);
67: MatScale(K,0.5);
69: /* D is a tridiagonal */
70: MatCreate(PETSC_COMM_WORLD,&D);
71: MatSetSizes(D,PETSC_DECIDE,PETSC_DECIDE,n,n);
72: MatSetFromOptions(D);
73: MatSetUp(D);
75: MatGetOwnershipRange(D,&Istart,&Iend);
76: for (j=Istart;j<Iend;j++) {
77: for (k=0;k<n;k++) {
78: 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);
79: }
80: }
82: MatAssemblyBegin(D,MAT_FINAL_ASSEMBLY);
83: MatAssemblyEnd(D,MAT_FINAL_ASSEMBLY);
84: MatScale(D,0.5);
86: /* M is a diagonal matrix */
87: MatCreate(PETSC_COMM_WORLD,&M);
88: MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
89: MatSetFromOptions(M);
90: MatSetUp(M);
91: MatGetOwnershipRange(M,&Istart,&Iend);
92: for (j=Istart;j<Iend;j++) MatSetValue(M,j,j,1.0,INSERT_VALUES);
93: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
94: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
95: MatScale(M,0.5);
97: /* add damping */
98: if (eta>0.0) {
99: MatAXPY(K,eta,D,DIFFERENT_NONZERO_PATTERN); /* K = K + eta*D */
100: MatShift(D,eta); /* D = D + eta*eye(n) */
101: }
103: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
104: Create the eigensolver and solve the problem
105: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
107: PEPCreate(PETSC_COMM_WORLD,&pep);
108: A[0] = K; A[1] = D; A[2] = M;
109: PEPSetOperators(pep,3,A);
110: if (eta==0.0) PEPSetProblemType(pep,PEP_GYROSCOPIC);
111: else PEPSetProblemType(pep,PEP_GENERAL);
112: PEPSetFromOptions(pep);
113: PEPSolve(pep);
115: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
116: Display solution and clean up
117: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
119: /* show detailed info unless -terse option is given by user */
120: PetscOptionsHasName(NULL,NULL,"-terse",&terse);
121: if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
122: else {
123: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
124: PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
125: PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
126: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
127: }
128: PEPDestroy(&pep);
129: MatDestroy(&M);
130: MatDestroy(&D);
131: MatDestroy(&K);
132: SlepcFinalize();
133: return 0;
134: }
136: /*TEST
138: testset:
139: args: -pep_nev 4 -terse
140: requires: double
141: output_file: output/wiresaw_1.out
142: test:
143: suffix: 1
144: args: -pep_type {{toar qarnoldi}}
145: test:
146: suffix: 1_linear_h1
147: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_linearization 1,0 -pep_linear_st_ksp_type bcgs -pep_linear_st_pc_type kaczmarz
148: test:
149: suffix: 1_linear_h2
150: args: -pep_type linear -pep_linear_explicitmatrix -pep_linear_linearization 0,1
152: TEST*/