EPSSetInterval#

Defines the computational interval for spectrum slicing.

Synopsis#

#include "slepceps.h" 
PetscErrorCode EPSSetInterval(EPS eps,PetscReal inta,PetscReal intb)

Logically Collective

Input Parameters#

  • eps - the linear eigensolver context

  • inta - left end of the interval

  • intb - right end of the interval

Options Database Key#

  • -eps_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. This function provides the interval to be considered. It must be used in combination with EPS_ALL, see EPSSetWhichEigenpairs().

A computational interval is also needed when using polynomial filters, see STFILTER and section Polynomial Filtering.

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

See Also#

EPS: Eigenvalue Problem Solver, Spectrum Slicing, Polynomial Filtering, EPSGetInterval(), EPSSetWhichEigenpairs(), STFILTER

Level#

intermediate

Location#

src/eps/interface/epsbasic.c

Examples#

src/eps/tutorials/ex12.c
src/eps/tutorials/ex25.c

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