Date: 2022-03-31T15:29:27+00:00

Actual source code: test6.c
slepc-3.17.0 2022-03-31
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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:    Example based on spring problem in NLEVP collection [1]. See the parameters
     12:    meaning at Example 2 in [2].

     14:    [1] T. Betcke, N. J. Higham, V. Mehrmann, C. Schroder, and F. Tisseur,
     15:        NLEVP: A Collection of Nonlinear Eigenvalue Problems, MIMS EPrint
     16:        2010.98, November 2010.
     17:    [2] F. Tisseur, Backward error and condition of polynomial eigenvalue
     18:        problems, Linear Algebra and its Applications, 309 (2000), pp. 339--361,
     19:        April 2000.
     20: */

     22: static char help[] = "Tests multiple calls to PEPSolve with different matrix of different size.\n\n"
     23:   "This is based on the spring problem from NLEVP collection.\n\n"
     24:   "The command line options are:\n"
     25:   "  -n <n> ... number of grid subdivisions.\n"
     26:   "  -mu <value> ... mass (default 1).\n"
     27:   "  -tau <value> ... damping constant of the dampers (default 10).\n"
     28:   "  -kappa <value> ... damping constant of the springs (default 5).\n"
     29:   "  -initv ... set an initial vector.\n\n";

     31: #include <slepcpep.h>

     33: int main(int argc,char **argv)
     34: {
     35:   Mat            M,C,K,A[3];      /* problem matrices */
     36:   PEP            pep;             /* polynomial eigenproblem solver context */
     37:   PetscInt       n=30,Istart,Iend,i,nev;
     38:   PetscReal      mu=1.0,tau=10.0,kappa=5.0;
     39:   PetscBool      terse=PETSC_FALSE;

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

     43:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     44:   PetscOptionsGetReal(NULL,NULL,"-mu",&mu,NULL);
     45:   PetscOptionsGetReal(NULL,NULL,"-tau",&tau,NULL);
     46:   PetscOptionsGetReal(NULL,NULL,"-kappa",&kappa,NULL);

     48:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     49:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     50:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     52:   /* K is a tridiagonal */
     53:   MatCreate(PETSC_COMM_WORLD,&K);
     54:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
     55:   MatSetFromOptions(K);
     56:   MatSetUp(K);

     58:   MatGetOwnershipRange(K,&Istart,&Iend);
     59:   for (i=Istart;i<Iend;i++) {
     60:     if (i>0) MatSetValue(K,i,i-1,-kappa,INSERT_VALUES);
     61:     MatSetValue(K,i,i,kappa*3.0,INSERT_VALUES);
     62:     if (i<n-1) MatSetValue(K,i,i+1,-kappa,INSERT_VALUES);
     63:   }

     65:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
     66:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

     68:   /* C is a tridiagonal */
     69:   MatCreate(PETSC_COMM_WORLD,&C);
     70:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
     71:   MatSetFromOptions(C);
     72:   MatSetUp(C);

     74:   MatGetOwnershipRange(C,&Istart,&Iend);
     75:   for (i=Istart;i<Iend;i++) {
     76:     if (i>0) MatSetValue(C,i,i-1,-tau,INSERT_VALUES);
     77:     MatSetValue(C,i,i,tau*3.0,INSERT_VALUES);
     78:     if (i<n-1) MatSetValue(C,i,i+1,-tau,INSERT_VALUES);
     79:   }

     81:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
     82:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

     84:   /* M is a diagonal matrix */
     85:   MatCreate(PETSC_COMM_WORLD,&M);
     86:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
     87:   MatSetFromOptions(M);
     88:   MatSetUp(M);
     89:   MatGetOwnershipRange(M,&Istart,&Iend);
     90:   for (i=Istart;i<Iend;i++) MatSetValue(M,i,i,mu,INSERT_VALUES);
     91:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
     92:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

     94:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     95:                 Create the eigensolver and set various options
     96:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     98:   PEPCreate(PETSC_COMM_WORLD,&pep);
     99:   A[0] = K; A[1] = C; A[2] = M;
    100:   PEPSetOperators(pep,3,A);
    101:   PEPSetProblemType(pep,PEP_GENERAL);
    102:   PEPSetTolerances(pep,PETSC_SMALL,PETSC_DEFAULT);
    103:   PEPSetFromOptions(pep);

    105:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    106:                       Solve the eigensystem
    107:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    109:   PEPSolve(pep);
    110:   PEPGetDimensions(pep,&nev,NULL,NULL);
    111:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);

    113:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    114:                       Display solution of first solve
    115:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    116:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
    117:   if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    118:   else {
    119:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    120:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
    121:     PEPErrorView(pep,PEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    122:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    123:   }
    124:   MatDestroy(&M);
    125:   MatDestroy(&C);
    126:   MatDestroy(&K);

    128:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    129:      Compute the eigensystem, (k^2*M+k*C+K)x=0 for bigger n
    130:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    132:   n *= 2;
    133:   /* K is a tridiagonal */
    134:   MatCreate(PETSC_COMM_WORLD,&K);
    135:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
    136:   MatSetFromOptions(K);
    137:   MatSetUp(K);

    139:   MatGetOwnershipRange(K,&Istart,&Iend);
    140:   for (i=Istart;i<Iend;i++) {
    141:     if (i>0) MatSetValue(K,i,i-1,-kappa,INSERT_VALUES);
    142:     MatSetValue(K,i,i,kappa*3.0,INSERT_VALUES);
    143:     if (i<n-1) MatSetValue(K,i,i+1,-kappa,INSERT_VALUES);
    144:   }

    146:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
    147:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

    149:   /* C is a tridiagonal */
    150:   MatCreate(PETSC_COMM_WORLD,&C);
    151:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
    152:   MatSetFromOptions(C);
    153:   MatSetUp(C);

    155:   MatGetOwnershipRange(C,&Istart,&Iend);
    156:   for (i=Istart;i<Iend;i++) {
    157:     if (i>0) MatSetValue(C,i,i-1,-tau,INSERT_VALUES);
    158:     MatSetValue(C,i,i,tau*3.0,INSERT_VALUES);
    159:     if (i<n-1) MatSetValue(C,i,i+1,-tau,INSERT_VALUES);
    160:   }

    162:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
    163:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

    165:   /* M is a diagonal matrix */
    166:   MatCreate(PETSC_COMM_WORLD,&M);
    167:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
    168:   MatSetFromOptions(M);
    169:   MatSetUp(M);
    170:   MatGetOwnershipRange(M,&Istart,&Iend);
    171:   for (i=Istart;i<Iend;i++) MatSetValue(M,i,i,mu,INSERT_VALUES);
    172:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
    173:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

    175:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    176:        Solve again, calling PEPReset() since matrix size has changed
    177:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    178:   /*PEPReset(pep);*/  /* not required, will be called in PEPSetOperators() */
    179:   A[0] = K; A[1] = C; A[2] = M;
    180:   PEPSetOperators(pep,3,A);
    181:   PEPSolve(pep);

    183:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    184:                     Display solution and clean up
    185:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    186:   if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    187:   else {
    188:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    189:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
    190:     PEPErrorView(pep,PEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    191:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    192:   }
    193:   PEPDestroy(&pep);
    194:   MatDestroy(&M);
    195:   MatDestroy(&C);
    196:   MatDestroy(&K);
    197:   SlepcFinalize();
    198:   return 0;
    199: }

    201: /*TEST

    203:    test:
    204:       suffix: 1
    205:       args: -pep_type {{toar qarnoldi linear}} -pep_nev 4 -terse
    206:       requires: !single

    208:    test:
    209:       suffix: 2
    210:       args: -pep_type stoar -pep_hermitian -pep_nev 4 -terse
    211:       requires: !single

    213: TEST*/