Date: 2024-12-02T08:57:06+00:00

Actual source code: test41.c
slepc-3.22.2 2024-12-02
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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 EVSL.\n\n"
     12:   "This is based on ex3.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;           /* matrix */
     21:   EPS            eps;         /* eigenproblem solver context */
     22:   PetscInt       N,n=20,m,Istart,Iend,II,i,j,nslice;
     23:   PetscReal      a,b,ra,rb;
     24:   PetscBool      flag;
     25:   EPSEVSLDamping damping;

     27:   PetscFunctionBeginUser;
     28:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));

     30:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     31:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
     32:   if (!flag) m=n;
     33:   N = n*m;
     34:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nStandard eigenproblem with EVSL, 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:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
     41:   PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N));
     42:   PetscCall(MatSetFromOptions(A));

     44:   PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
     45:   for (II=Istart;II<Iend;II++) {
     46:     i = II/n; j = II-i*n;
     47:     if (i>0) PetscCall(MatSetValue(A,II,II-n,-1.0,INSERT_VALUES));
     48:     if (i<m-1) PetscCall(MatSetValue(A,II,II+n,-1.0,INSERT_VALUES));
     49:     if (j>0) PetscCall(MatSetValue(A,II,II-1,-1.0,INSERT_VALUES));
     50:     if (j<n-1) PetscCall(MatSetValue(A,II,II+1,-1.0,INSERT_VALUES));
     51:     PetscCall(MatSetValue(A,II,II,4.0,INSERT_VALUES));
     52:   }

     54:   PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
     55:   PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));

     57:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     58:                 Create the eigensolver and set various options
     59:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     61:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
     62:   PetscCall(EPSSetOperators(eps,A,NULL));
     63:   PetscCall(EPSSetProblemType(eps,EPS_HEP));
     64:   PetscCall(EPSSetType(eps,EPSEVSL));

     66:   /*
     67:      Set several options
     68:   */
     69:   PetscCall(EPSSetInterval(eps,1.3,1.44));
     70:   PetscCall(EPSEVSLSetRange(eps,0,8));
     71:   PetscCall(EPSEVSLSetSlices(eps,3));
     72:   PetscCall(EPSEVSLSetDamping(eps,EPS_EVSL_DAMPING_SIGMA));
     73:   PetscCall(EPSEVSLSetDOSParameters(eps,EPS_EVSL_DOS_KPM,50,450,PETSC_CURRENT,PETSC_CURRENT));
     74:   PetscCall(EPSEVSLSetPolParameters(eps,4000,0.85));
     75:   PetscCall(EPSSetFromOptions(eps));

     77:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     78:            Compute all eigenvalues in interval and display info
     79:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     81:   PetscCall(EPSSolve(eps));
     82:   PetscCall(EPSEVSLGetSlices(eps,&nslice));
     83:   PetscCall(EPSGetInterval(eps,&a,&b));
     84:   PetscCall(EPSEVSLGetRange(eps,&ra,&rb));
     85:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," EVSL: solving interval [%g,%g] with %" PetscInt_FMT " slices (spectral range [%g,%g])\n",a,b,nslice,ra,rb));
     86:   PetscCall(EPSEVSLGetDamping(eps,&damping));
     87:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," EVSL: damping type is %s\n",EPSEVSLDampings[damping]));

     89:   PetscCall(EPSView(eps,NULL));
     90:   PetscCall(EPSErrorView(eps,EPS_ERROR_ABSOLUTE,NULL));

     92:   PetscCall(EPSDestroy(&eps));
     93:   PetscCall(MatDestroy(&A));
     94:   PetscCall(SlepcFinalize());
     95:   return 0;
     96: }

     98: /*TEST

    100:    build:
    101:       requires: evsl

    103:    test:
    104:       requires: evsl
    105:       args: -eps_evsl_damping none
    106:       filter: grep -v ncv

    108: TEST*/