Date: 2022-10-01T06:40:30+00:00

Actual source code: sleeper.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 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.

     18:    The sleeper problem is a proportionally damped QEP describing the
     19:    oscillations of a rail track resting on sleepers.
     20: */

     22: static char help[] = "Oscillations of a rail track resting on sleepers.\n\n"
     23:   "The command line options are:\n"
     24:   "  -n <n>, where <n> = dimension of the matrices.\n\n";

     26: #include <slepcpep.h>

     28: int main(int argc,char **argv)
     29: {
     30:   Mat            M,C,K,A[3];      /* problem matrices */
     31:   PEP            pep;             /* polynomial eigenproblem solver context */
     32:   PetscInt       n=10,Istart,Iend,i;
     33:   PetscBool      terse;

     36:   SlepcInitialize(&argc,&argv,(char*)0,help);

     38:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     39:   PetscPrintf(PETSC_COMM_WORLD,"\nRailtrack resting on sleepers, n=%" PetscInt_FMT "\n\n",n);

     41:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     42:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     43:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     45:   /* K is a pentadiagonal */
     46:   MatCreate(PETSC_COMM_WORLD,&K);
     47:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
     48:   MatSetFromOptions(K);
     49:   MatSetUp(K);

     51:   MatGetOwnershipRange(K,&Istart,&Iend);
     52:   for (i=Istart;i<Iend;i++) {
     53:     if (i==0) {
     54:       MatSetValue(K,i,n-1,-3.0,INSERT_VALUES);
     55:       MatSetValue(K,i,n-2,1.0,INSERT_VALUES);
     56:     }
     57:     if (i==1) MatSetValue(K,i,n-1,1.0,INSERT_VALUES);
     58:     if (i>0) MatSetValue(K,i,i-1,-3.0,INSERT_VALUES);
     59:     if (i>1) MatSetValue(K,i,i-2,1.0,INSERT_VALUES);
     60:     MatSetValue(K,i,i,5.0,INSERT_VALUES);
     61:     if (i==n-1) {
     62:       MatSetValue(K,i,0,-3.0,INSERT_VALUES);
     63:       MatSetValue(K,i,1,1.0,INSERT_VALUES);
     64:     }
     65:     if (i==n-2) MatSetValue(K,i,0,1.0,INSERT_VALUES);
     66:     if (i<n-1) MatSetValue(K,i,i+1,-3.0,INSERT_VALUES);
     67:     if (i<n-2) MatSetValue(K,i,i+2,1.0,INSERT_VALUES);
     68:   }

     70:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
     71:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

     73:   /* C is a circulant matrix */
     74:   MatCreate(PETSC_COMM_WORLD,&C);
     75:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
     76:   MatSetFromOptions(C);
     77:   MatSetUp(C);

     79:   MatGetOwnershipRange(C,&Istart,&Iend);
     80:   for (i=Istart;i<Iend;i++) {
     81:     if (i==0) {
     82:       MatSetValue(C,i,n-1,-4.0,INSERT_VALUES);
     83:       MatSetValue(C,i,n-2,1.0,INSERT_VALUES);
     84:     }
     85:     if (i==1) MatSetValue(C,i,n-1,1.0,INSERT_VALUES);
     86:     if (i>0) MatSetValue(C,i,i-1,-4.0,INSERT_VALUES);
     87:     if (i>1) MatSetValue(C,i,i-2,1.0,INSERT_VALUES);
     88:     MatSetValue(C,i,i,7.0,INSERT_VALUES);
     89:     if (i==n-1) {
     90:       MatSetValue(C,i,0,-4.0,INSERT_VALUES);
     91:       MatSetValue(C,i,1,1.0,INSERT_VALUES);
     92:     }
     93:     if (i==n-2) MatSetValue(C,i,0,1.0,INSERT_VALUES);
     94:     if (i<n-1) MatSetValue(C,i,i+1,-4.0,INSERT_VALUES);
     95:     if (i<n-2) MatSetValue(C,i,i+2,1.0,INSERT_VALUES);
     96:   }

     98:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
     99:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

    101:   /* M is the identity matrix */
    102:   MatCreate(PETSC_COMM_WORLD,&M);
    103:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
    104:   MatSetFromOptions(M);
    105:   MatSetUp(M);
    106:   MatGetOwnershipRange(M,&Istart,&Iend);
    107:   for (i=Istart;i<Iend;i++) MatSetValue(M,i,i,1.0,INSERT_VALUES);
    108:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
    109:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

    111:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    112:                 Create the eigensolver and solve the problem
    113:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    115:   PEPCreate(PETSC_COMM_WORLD,&pep);
    116:   A[0] = K; A[1] = C; A[2] = M;
    117:   PEPSetOperators(pep,3,A);
    118:   PEPSetFromOptions(pep);
    119:   PEPSolve(pep);

    121:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    122:                     Display solution and clean up
    123:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    125:   /* show detailed info unless -terse option is given by user */
    126:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
    127:   if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    128:   else {
    129:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    130:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
    131:     PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
    132:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    133:   }
    134:   PEPDestroy(&pep);
    135:   MatDestroy(&M);
    136:   MatDestroy(&C);
    137:   MatDestroy(&K);
    138:   SlepcFinalize();
    139:   return 0;
    140: }

    142: /*TEST

    144:    testset:
    145:       args: -n 100 -pep_nev 4 -pep_ncv 24 -st_type sinvert -terse
    146:       output_file: output/sleeper_1.out
    147:       requires: !single
    148:       filter: sed -e "s/[+-]0\.0*i//g"
    149:       test:
    150:          suffix: 1
    151:          args: -pep_type {{toar linear}} -pep_ncv 20
    152:       test:
    153:          suffix: 1_qarnoldi
    154:          args: -pep_type qarnoldi -pep_qarnoldi_restart 0.4

    156:    testset:
    157:       args: -n 24 -pep_nev 4 -pep_ncv 9 -pep_target -.62 -terse
    158:       output_file: output/sleeper_2.out
    159:       test:
    160:          suffix: 2_toar
    161:          args: -pep_type toar -pep_toar_restart .3 -st_type sinvert
    162:       test:
    163:          suffix: 2_jd
    164:          args: -pep_type jd -pep_jd_restart .3 -pep_jd_projection orthogonal

    166:    test:
    167:       suffix: 3
    168:       args: -n 275 -pep_type stoar -pep_hermitian -st_type sinvert -pep_nev 2 -pep_target -.89 -terse
    169:       requires: !single

    171:    test:
    172:       suffix: 4
    173:       args: -n 270 -pep_type stoar -pep_hermitian -pep_interval -3,-2.51 -st_type sinvert -st_pc_type cholesky -terse
    174:       requires: !single

    176: TEST*/