Date: 2013-09-02T10:07:33+00:00

Actual source code: test1.c

      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2013, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.

      8:    SLEPc is free software: you can redistribute it and/or modify it under  the
      9:    terms of version 3 of the GNU Lesser General Public License as published by
     10:    the Free Software Foundation.

     12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
     13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
     14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
     15:    more details.

     17:    You  should have received a copy of the GNU Lesser General  Public  License
     18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
     19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     20: */

     22: static char help[] = "Test the solution of a QEP without calling QEPSetFromOptions (based on ex16.c).\n\n"
     23:   "The command line options are:\n"
     24:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
     25:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n"
     26:   "  -type <qep_type> = qep type to test.\n"
     27:   "  -epstype <eps_type> = eps type to test (for linear).\n\n";

     29: #include <slepcqep.h>

     33: int main(int argc,char **argv)
     34: {
     35:   Mat            M,C,K;           /* problem matrices */
     36:   QEP            qep;             /* quadratic eigenproblem solver context */
     37:   QEPType        type;
     38:   PetscInt       N,n=10,m,Istart,Iend,II,nev,maxit,i,j;
     39:   PetscBool      flag,isgd2;
     40:   char           qeptype[30] = "linear",epstype[30] = "";
     41:   EPS            eps;
     42:   ST             st;
     43:   KSP            ksp;
     44:   PC             pc;

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

     49:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
     50:   PetscOptionsGetInt(NULL,"-m",&m,&flag);
     51:   if (!flag) m=n;
     52:   N = n*m;
     53:   PetscOptionsGetString(NULL,"-type",qeptype,30,NULL);
     54:   PetscOptionsGetString(NULL,"-epstype",epstype,30,&flag);
     55:   PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%D (%Dx%D grid)",N,n,m);
     56:   PetscPrintf(PETSC_COMM_WORLD,"\nQEP type: %s",qeptype);
     57:   if (flag) {
     58:     PetscPrintf(PETSC_COMM_WORLD,"\nEPS type: %s",epstype);
     59:   }
     60:   PetscPrintf(PETSC_COMM_WORLD,"\n\n");

     62:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     63:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     64:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     66:   /* K is the 2-D Laplacian */
     67:   MatCreate(PETSC_COMM_WORLD,&K);
     68:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N);
     69:   MatSetFromOptions(K);
     70:   MatSetUp(K);

     72:   MatGetOwnershipRange(K,&Istart,&Iend);
     73:   for (II=Istart;II<Iend;II++) {
     74:     i = II/n; j = II-i*n;
     75:     if (i>0) { MatSetValue(K,II,II-n,-1.0,INSERT_VALUES); }
     76:     if (i<m-1) { MatSetValue(K,II,II+n,-1.0,INSERT_VALUES); }
     77:     if (j>0) { MatSetValue(K,II,II-1,-1.0,INSERT_VALUES); }
     78:     if (j<n-1) { MatSetValue(K,II,II+1,-1.0,INSERT_VALUES); }
     79:     MatSetValue(K,II,II,4.0,INSERT_VALUES);
     80:   }

     82:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
     83:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

     85:   /* C is the zero matrix */
     86:   MatCreate(PETSC_COMM_WORLD,&C);
     87:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N);
     88:   MatSetFromOptions(C);
     89:   MatSetUp(C);
     90:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
     91:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

     93:   /* M is the identity matrix */
     94:   MatCreate(PETSC_COMM_WORLD,&M);
     95:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N);
     96:   MatSetFromOptions(M);
     97:   MatSetUp(M);
     98:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
     99:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
    100:   MatShift(M,1.0);

    102:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    103:                 Create the eigensolver and set various options
    104:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    106:   /*
    107:      Create eigensolver context
    108:   */
    109:   QEPCreate(PETSC_COMM_WORLD,&qep);

    111:   /*
    112:      Set matrices and problem type
    113:   */
    114:   QEPSetOperators(qep,M,C,K);
    115:   QEPSetProblemType(qep,QEP_GENERAL);
    116:   QEPSetDimensions(qep,4,20,PETSC_DEFAULT);
    117:   QEPSetTolerances(qep,PETSC_SMALL,PETSC_DEFAULT);

    119:   /*
    120:      Set solver type at runtime
    121:   */
    122:   QEPSetType(qep,qeptype);
    123:   if (flag) {
    124:     PetscObjectTypeCompare((PetscObject)qep,QEPLINEAR,&flag);
    125:     if (flag) {
    126:       QEPLinearGetEPS(qep,&eps);
    127:       PetscStrcmp(epstype,"gd2",&isgd2);
    128:       if (isgd2) {
    129:         EPSSetType(eps,EPSGD);
    130:         EPSGDSetDoubleExpansion(eps,PETSC_TRUE);
    131:       } else {
    132:         EPSSetType(eps,epstype);
    133:       }
    134:       EPSGetST(eps,&st);
    135:       STGetKSP(st,&ksp);
    136:       KSPGetPC(ksp,&pc);
    137:       PCSetType(pc,PCJACOBI);
    138:       PetscObjectTypeCompare((PetscObject)eps,EPSGD,&flag);
    139:     }
    140:   }

    142:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    143:                       Solve the eigensystem
    144:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    146:   QEPSolve(qep);

    148:   /*
    149:      Optional: Get some information from the solver and display it
    150:   */
    151:   QEPGetType(qep,&type);
    152:   PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
    153:   QEPGetDimensions(qep,&nev,NULL,NULL);
    154:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
    155:   QEPGetTolerances(qep,NULL,&maxit);
    156:   PetscPrintf(PETSC_COMM_WORLD," Stopping condition: maxit=%D\n",maxit);

    158:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    159:                     Display solution and clean up
    160:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    162:   QEPPrintSolution(qep,NULL);

    164:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    165:      Free work space
    166:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    168:   QEPDestroy(&qep);
    169:   MatDestroy(&M);
    170:   MatDestroy(&C);
    171:   MatDestroy(&K);
    172:   SlepcFinalize();
    173:   return 0;
    174: }