Actual source code: wiresaw.c

slepc-3.18.0 2022-10-01
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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 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*/