Date: 2015-09-03T15:05:48+00:00

Actual source code: butterfly.c
slepc-3.6.1 2015-09-03
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2015, 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: */
     21: /*
     22:    This example implements one of the problems found at
     23:        NLEVP: A Collection of Nonlinear Eigenvalue Problems,
     24:        The University of Manchester.
     25:    The details of the collection can be found at:
     26:        [1] T. Betcke et al., "NLEVP: A Collection of Nonlinear Eigenvalue
     27:            Problems", ACM Trans. Math. Software 39(2), Article 7, 2013.

     29:    The butterfly problem is a quartic PEP with T-even structure.
     30: */

     32: static char help[] = "NLEVP problem: butterfly.\n\n"
     33:   "The command line options are:\n"
     34:   "  -m <m>, grid size, the dimension of the matrices is n=m*m.\n"
     35:   "  -c <array>, problem parameters, must be 10 comma-separated real values.\n\n";

     37: #include <slepcpep.h>

     39: #define NMAT 5

     43: int main(int argc,char **argv)
     44: {
     45:   Mat            A[NMAT];         /* problem matrices */
     46:   PEP            pep;             /* polynomial eigenproblem solver context */
     47:   PetscInt       n,m=8,k,II,Istart,Iend,i,j;
     48:   PetscReal      c[10] = { 0.6, 1.3, 1.3, 0.1, 0.1, 1.2, 1.0, 1.0, 1.2, 1.0 };
     49:   PetscBool      flg;
     50:   PetscBool      terse;

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

     55:   PetscOptionsGetInt(NULL,"-m",&m,NULL);
     56:   n = m*m;
     57:   k = 10;
     58:   PetscOptionsGetRealArray(NULL,"-c",c,&k,&flg);
     59:   if (flg && k!=10) SETERRQ1(PETSC_COMM_WORLD,1,"The number of parameters -c should be 10, you provided %D",k);
     60:   PetscPrintf(PETSC_COMM_WORLD,"\nButterfly problem, n=%D (m=%D)\n\n",n,m);

     62:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     63:                      Compute the polynomial matrices
     64:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     66:   /* initialize matrices */
     67:   for (i=0;i<NMAT;i++) {
     68:     MatCreate(PETSC_COMM_WORLD,&A[i]);
     69:     MatSetSizes(A[i],PETSC_DECIDE,PETSC_DECIDE,n,n);
     70:     MatSetFromOptions(A[i]);
     71:     MatSetUp(A[i]);
     72:   }
     73:   MatGetOwnershipRange(A[0],&Istart,&Iend);

     75:   /* A0 */
     76:   for (II=Istart;II<Iend;II++) {
     77:     i = II/m; j = II-i*m;
     78:     MatSetValue(A[0],II,II,4.0*c[0]/6.0+4.0*c[1]/6.0,INSERT_VALUES);
     79:     if (j>0) { MatSetValue(A[0],II,II-1,c[0]/6.0,INSERT_VALUES); }
     80:     if (j<m-1) { MatSetValue(A[0],II,II+1,c[0]/6.0,INSERT_VALUES); }
     81:     if (i>0) { MatSetValue(A[0],II,II-m,c[1]/6.0,INSERT_VALUES); }
     82:     if (i<m-1) { MatSetValue(A[0],II,II+m,c[1]/6.0,INSERT_VALUES); }
     83:   }

     85:   /* A1 */
     86:   for (II=Istart;II<Iend;II++) {
     87:     i = II/m; j = II-i*m;
     88:     if (j>0) { MatSetValue(A[1],II,II-1,c[2],INSERT_VALUES); }
     89:     if (j<m-1) { MatSetValue(A[1],II,II+1,-c[2],INSERT_VALUES); }
     90:     if (i>0) { MatSetValue(A[1],II,II-m,c[3],INSERT_VALUES); }
     91:     if (i<m-1) { MatSetValue(A[1],II,II+m,-c[3],INSERT_VALUES); }
     92:   }

     94:   /* A2 */
     95:   for (II=Istart;II<Iend;II++) {
     96:     i = II/m; j = II-i*m;
     97:     MatSetValue(A[2],II,II,-2.0*c[4]-2.0*c[5],INSERT_VALUES);
     98:     if (j>0) { MatSetValue(A[2],II,II-1,c[4],INSERT_VALUES); }
     99:     if (j<m-1) { MatSetValue(A[2],II,II+1,c[4],INSERT_VALUES); }
    100:     if (i>0) { MatSetValue(A[2],II,II-m,c[5],INSERT_VALUES); }
    101:     if (i<m-1) { MatSetValue(A[2],II,II+m,c[5],INSERT_VALUES); }
    102:   }

    104:   /* A3 */
    105:   for (II=Istart;II<Iend;II++) {
    106:     i = II/m; j = II-i*m;
    107:     if (j>0) { MatSetValue(A[3],II,II-1,c[6],INSERT_VALUES); }
    108:     if (j<m-1) { MatSetValue(A[3],II,II+1,-c[6],INSERT_VALUES); }
    109:     if (i>0) { MatSetValue(A[3],II,II-m,c[7],INSERT_VALUES); }
    110:     if (i<m-1) { MatSetValue(A[3],II,II+m,-c[7],INSERT_VALUES); }
    111:   }

    113:   /* A4 */
    114:   for (II=Istart;II<Iend;II++) {
    115:     i = II/m; j = II-i*m;
    116:     MatSetValue(A[4],II,II,2.0*c[8]+2.0*c[9],INSERT_VALUES);
    117:     if (j>0) { MatSetValue(A[4],II,II-1,-c[8],INSERT_VALUES); }
    118:     if (j<m-1) { MatSetValue(A[4],II,II+1,-c[8],INSERT_VALUES); }
    119:     if (i>0) { MatSetValue(A[4],II,II-m,-c[9],INSERT_VALUES); }
    120:     if (i<m-1) { MatSetValue(A[4],II,II+m,-c[9],INSERT_VALUES); }
    121:   }

    123:   /* assemble matrices */
    124:   for (i=0;i<NMAT;i++) {
    125:     MatAssemblyBegin(A[i],MAT_FINAL_ASSEMBLY);
    126:   }
    127:   for (i=0;i<NMAT;i++) {
    128:     MatAssemblyEnd(A[i],MAT_FINAL_ASSEMBLY);
    129:   }

    131:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    132:                 Create the eigensolver and solve the problem
    133:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    135:   PEPCreate(PETSC_COMM_WORLD,&pep);
    136:   PEPSetOperators(pep,NMAT,A);
    137:   PEPSetFromOptions(pep);
    138:   PEPSolve(pep);

    140:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    141:                     Display solution and clean up
    142:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    143:
    144:   /* show detailed info unless -terse option is given by user */
    145:   PetscOptionsHasName(NULL,"-terse",&terse);
    146:   if (terse) {
    147:     PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    148:   } else {
    149:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    150:     PEPReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
    151:     PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
    152:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    153:   }
    154:   PEPDestroy(&pep);
    155:   for (i=0;i<NMAT;i++) {
    156:     MatDestroy(&A[i]);
    157:   }
    158:   SlepcFinalize();
    159:   return 0;
    160: }