NEPSetWhichEigenpairs#

Specifies which portion of the spectrum is to be sought.

Synopsis#

#include "slepcnep.h" 
PetscErrorCode NEPSetWhichEigenpairs(NEP nep,NEPWhich which)

Logically Collective

Input Parameters#

  • nep - eigensolver context obtained from NEPCreate()

  • which - the portion of the spectrum to be sought

Options Database Keys#

  • -nep_largest_magnitude - Sets largest eigenvalues in magnitude

  • -nep_smallest_magnitude - Sets smallest eigenvalues in magnitude

  • -nep_largest_real - Sets largest real parts

  • -nep_smallest_real - Sets smallest real parts

  • -nep_largest_imaginary - Sets largest imaginary parts

  • -nep_smallest_imaginary - Sets smallest imaginary parts

  • -nep_target_magnitude - Sets eigenvalues closest to target

  • -nep_target_real - Sets real parts closest to target

  • -nep_target_imaginary - Sets imaginary parts closest to target

  • -nep_all - Sets all eigenvalues in a region

Notes#

The parameter ‘which’ can have one of these values

  • NEP_LARGEST_MAGNITUDE - largest eigenvalues in magnitude (default)

  • NEP_SMALLEST_MAGNITUDE - smallest eigenvalues in magnitude

  • NEP_LARGEST_REAL - largest real parts

  • NEP_SMALLEST_REAL - smallest real parts

  • NEP_LARGEST_IMAGINARY - largest imaginary parts

  • NEP_SMALLEST_IMAGINARY - smallest imaginary parts

  • NEP_TARGET_MAGNITUDE - eigenvalues closest to the target (in magnitude)

  • NEP_TARGET_REAL - eigenvalues with real part closest to target

  • NEP_TARGET_IMAGINARY - eigenvalues with imaginary part closest to target

  • NEP_ALL - all eigenvalues contained in a given region

  • NEP_WHICH_USER - user defined ordering set with NEPSetEigenvalueComparison()

Not all eigensolvers implemented in NEP account for all the possible values stated above. If SLEPc is compiled for real numbers NEP_LARGEST_IMAGINARY and NEP_SMALLEST_IMAGINARY use the absolute value of the imaginary part for eigenvalue selection.

The target is a scalar value provided with NEPSetTarget().

NEP_ALL is intended for use in the context of the CISS solver for computing all eigenvalues in a region.

See Also#

NEPGetWhichEigenpairs(), NEPSetTarget(), NEPSetEigenvalueComparison(), NEPWhich

Level#

intermediate

Location#

src/nep/interface/nepopts.c

Index of all NEP routines Table of Contents for all manual pages Index of all manual pages