Date: 2022-08-09T09:05:39+00:00

Actual source code: test35.c
slepc-3.17.2 2022-08-09
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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: */

     11: static char help[] = "Test interface to external package BLOPEX.\n\n"
     12:   "This is based on ex12.c. The command line options are:\n"
     13:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
     14:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

     16: #include <slepceps.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Mat            A,B;         /* matrices */
     21:   EPS            eps;         /* eigenproblem solver context */
     22:   ST             st;          /* spectral transformation context */
     23:   KSP            ksp;
     24:   PC             pc;
     25:   PetscInt       N,n=35,m,Istart,Iend,II,i,j,bs;
     26:   PetscBool      flag;

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

     30:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     31:   PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
     32:   if (!flag) m=n;
     33:   N = n*m;
     34:   PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized eigenproblem with BLOPEX, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);

     36:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     37:      Compute the matrices that define the eigensystem, Ax=kBx
     38:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     40:   MatCreate(PETSC_COMM_WORLD,&A);
     41:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
     42:   MatSetFromOptions(A);
     43:   MatSetUp(A);

     45:   MatCreate(PETSC_COMM_WORLD,&B);
     46:   MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
     47:   MatSetFromOptions(B);
     48:   MatSetUp(B);

     50:   MatGetOwnershipRange(A,&Istart,&Iend);
     51:   for (II=Istart;II<Iend;II++) {
     52:     i = II/n; j = II-i*n;
     53:     if (i>0) MatSetValue(A,II,II-n,-1.0,INSERT_VALUES);
     54:     if (i<m-1) MatSetValue(A,II,II+n,-1.0,INSERT_VALUES);
     55:     if (j>0) MatSetValue(A,II,II-1,-1.0,INSERT_VALUES);
     56:     if (j<n-1) MatSetValue(A,II,II+1,-1.0,INSERT_VALUES);
     57:     MatSetValue(A,II,II,4.0,INSERT_VALUES);
     58:     MatSetValue(B,II,II,2.0,INSERT_VALUES);
     59:   }
     60:   if (Istart==0) {
     61:     MatSetValue(B,0,0,6.0,INSERT_VALUES);
     62:     MatSetValue(B,0,1,-1.0,INSERT_VALUES);
     63:     MatSetValue(B,1,0,-1.0,INSERT_VALUES);
     64:     MatSetValue(B,1,1,1.0,INSERT_VALUES);
     65:   }

     67:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     68:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
     69:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
     70:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

     72:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     73:                 Create the eigensolver and set various options
     74:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     76:   EPSCreate(PETSC_COMM_WORLD,&eps);
     77:   EPSSetOperators(eps,A,B);
     78:   EPSSetProblemType(eps,EPS_GHEP);
     79:   EPSSetType(eps,EPSBLOPEX);

     81:   /*
     82:      Set several options
     83:   */
     84:   EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL);
     85:   EPSGetST(eps,&st);
     86:   STSetType(st,STPRECOND);
     87:   STGetKSP(st,&ksp);
     88:   KSPGetPC(ksp,&pc);
     89:   KSPSetType(ksp,KSPPREONLY);
     90:   PCSetType(pc,PCICC);

     92:   EPSBLOPEXSetBlockSize(eps,4);
     93:   EPSSetFromOptions(eps);

     95:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     96:            Compute all eigenvalues in interval and display info
     97:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     99:   EPSSolve(eps);
    100:   EPSBLOPEXGetBlockSize(eps,&bs);
    101:   PetscPrintf(PETSC_COMM_WORLD," BLOPEX: using block size %" PetscInt_FMT "\n",bs);

    103:   EPSErrorView(eps,EPS_ERROR_ABSOLUTE,NULL);

    105:   EPSDestroy(&eps);
    106:   MatDestroy(&A);
    107:   MatDestroy(&B);
    108:   SlepcFinalize();
    109:   return 0;
    110: }

    112: /*TEST

    114:    build:
    115:       requires: blopex

    117:    test:
    118:       suffix: 1
    119:       args: -eps_nev 8 -eps_view
    120:       requires: blopex
    121:       filter: grep -v tolerance | sed -e "s/hermitian/symmetric/"

    123: TEST*/