Date: 2021-09-20T09:44:06+00:00

Actual source code: test6.c
slepc-3.15.2 2021-09-20
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2021, 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 */
     38:   PetscInt       n=30,Istart,Iend,i,nev;
     39:   PetscReal      mu=1.0,tau=10.0,kappa=5.0;
     40:   PetscBool      terse=PETSC_FALSE;

     42:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;

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

     49:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     50:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     51:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

     59:   MatGetOwnershipRange(K,&Istart,&Iend);
     60:   for (i=Istart;i<Iend;i++) {
     61:     if (i>0) {
     62:       MatSetValue(K,i,i-1,-kappa,INSERT_VALUES);
     63:     }
     64:     MatSetValue(K,i,i,kappa*3.0,INSERT_VALUES);
     65:     if (i<n-1) {
     66:       MatSetValue(K,i,i+1,-kappa,INSERT_VALUES);
     67:     }
     68:   }

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

     73:   /* C is a tridiagonal */
     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,i-1,-tau,INSERT_VALUES);
     83:     }
     84:     MatSetValue(C,i,i,tau*3.0,INSERT_VALUES);
     85:     if (i<n-1) {
     86:       MatSetValue(C,i,i+1,-tau,INSERT_VALUES);
     87:     }
     88:   }

     90:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
     91:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

     93:   /* M is a diagonal matrix */
     94:   MatCreate(PETSC_COMM_WORLD,&M);
     95:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
     96:   MatSetFromOptions(M);
     97:   MatSetUp(M);
     98:   MatGetOwnershipRange(M,&Istart,&Iend);
     99:   for (i=Istart;i<Iend;i++) {
    100:     MatSetValue(M,i,i,mu,INSERT_VALUES);
    101:   }
    102:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
    103:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

    105:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    106:                 Create the eigensolver and set various options
    107:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    109:   PEPCreate(PETSC_COMM_WORLD,&pep);
    110:   A[0] = K; A[1] = C; A[2] = M;
    111:   PEPSetOperators(pep,3,A);
    112:   PEPSetProblemType(pep,PEP_GENERAL);
    113:   PEPSetTolerances(pep,PETSC_SMALL,PETSC_DEFAULT);
    114:   PEPSetFromOptions(pep);

    116:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    117:                       Solve the eigensystem
    118:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    120:   PEPSolve(pep);
    121:   PEPGetDimensions(pep,&nev,NULL,NULL);
    122:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);

    124:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    125:                       Display solution of first solve
    126:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    127:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
    128:   if (terse) {
    129:     PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    130:   } else {
    131:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    132:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
    133:     PEPErrorView(pep,PEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    134:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    135:   }
    136:   MatDestroy(&M);
    137:   MatDestroy(&C);
    138:   MatDestroy(&K);

    140:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    141:      Compute the eigensystem, (k^2*M+k*C+K)x=0 for bigger n
    142:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    144:   n *= 2;
    145:   /* K is a tridiagonal */
    146:   MatCreate(PETSC_COMM_WORLD,&K);
    147:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n);
    148:   MatSetFromOptions(K);
    149:   MatSetUp(K);

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

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

    165:   /* C is a tridiagonal */
    166:   MatCreate(PETSC_COMM_WORLD,&C);
    167:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n);
    168:   MatSetFromOptions(C);
    169:   MatSetUp(C);

    171:   MatGetOwnershipRange(C,&Istart,&Iend);
    172:   for (i=Istart;i<Iend;i++) {
    173:     if (i>0) {
    174:       MatSetValue(C,i,i-1,-tau,INSERT_VALUES);
    175:     }
    176:     MatSetValue(C,i,i,tau*3.0,INSERT_VALUES);
    177:     if (i<n-1) {
    178:       MatSetValue(C,i,i+1,-tau,INSERT_VALUES);
    179:     }
    180:   }

    182:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
    183:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

    185:   /* M is a diagonal matrix */
    186:   MatCreate(PETSC_COMM_WORLD,&M);
    187:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n);
    188:   MatSetFromOptions(M);
    189:   MatSetUp(M);
    190:   MatGetOwnershipRange(M,&Istart,&Iend);
    191:   for (i=Istart;i<Iend;i++) {
    192:     MatSetValue(M,i,i,mu,INSERT_VALUES);
    193:   }
    194:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
    195:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

    197:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    198:        Solve again, calling PEPReset() since matrix size has changed
    199:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    200:   /*PEPReset(pep);*/  /* not required, will be called in PEPSetOperators() */
    201:   A[0] = K; A[1] = C; A[2] = M;
    202:   PEPSetOperators(pep,3,A);
    203:   PEPSolve(pep);

    205:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    206:                     Display solution and clean up
    207:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    208:   if (terse) {
    209:     PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    210:   } else {
    211:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    212:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
    213:     PEPErrorView(pep,PEP_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    214:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    215:   }
    216:   PEPDestroy(&pep);
    217:   MatDestroy(&M);
    218:   MatDestroy(&C);
    219:   MatDestroy(&K);
    220:   SlepcFinalize();
    221:   return ierr;
    222: }

    224: /*TEST

    226:    test:
    227:       suffix: 1
    228:       args: -pep_type {{toar qarnoldi linear}} -pep_nev 4 -terse
    229:       requires: !single

    231:    test:
    232:       suffix: 2
    233:       args: -pep_type stoar -pep_hermitian -pep_nev 4 -terse
    234:       requires: !single

    236: TEST*/