PEPSetInterval#

Defines the computational interval for spectrum slicing.

Synopsis#

#include "slepcpep.h" 
PetscErrorCode PEPSetInterval(PEP pep,PetscReal inta,PetscReal intb)

Logically Collective

Input Parameters#

  • pep - the polynomial eigensolver context

  • inta - left end of the interval

  • intb - right end of the interval

Options Database Key#

  • -pep_interval <a,b> - set \([a,b]\) as the interval of interest

Notes#

Spectrum slicing is a technique employed for computing all eigenvalues of symmetric eigenproblems in a given interval, see section Spectrum Slicing for PEP. This function provides the interval to be considered. It must be used in combination with PEP_ALL, see PEPSetWhichEigenpairs(). Note that in polynomial eigenproblems spectrum slicing is implemented in PEPSTOAR only.

In the command-line option, two values must be provided. For an open interval, one can give an infinite, e.g., -pep_interval 1.0,inf or -pep_interval -inf,1.0. An open interval in the programmatic interface can be specified with PETSC_MAX_REAL and -PETSC_MAX_REAL.

See Also#

PEP: Polynomial Eigenvalue Problems, Spectrum Slicing for PEP, PEPGetInterval(), PEPSetWhichEigenpairs(), PEPSTOAR

Level#

intermediate

Location#

src/pep/interface/pepbasic.c

Examples#

src/pep/tutorials/ex38.c
src/pep/tutorials/ex40.c

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