Actual source code: test41.c

slepc-3.17.0 2022-03-31
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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:   SlepcInitialize(&argc,&argv,(char*)0,help);

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

 35:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 36:      Compute the matrices that define the eigensystem, Ax=kBx
 37:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

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

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

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

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

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

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

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

 92:   EPSDestroy(&eps);
 93:   MatDestroy(&A);
 94:   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*/