# EPSSetLeftVectorsWanted

Specifies which eigenvectors are required.

### Synopsis

    #include "slepceps.h"
    PetscErrorCode EPSSetLeftVectorsWanted(EPS eps,PetscBool leftvecs)

Logically Collective on EPS

### Input Parameters

| eps | - the eigensolver context
| leftvecs | - whether left eigenvectors are required or not

### Options Database Keys

-eps_left_vectors <boolean> - Sets/resets the boolean flag 'leftvecs'

### Notes

If the user sets leftvecs=PETSC_TRUE then the solver uses a variant of the algorithm that computes both right and left eigenvectors. This is usually much more costly. This option is not available in all solvers.

### See Also

EPSGetLeftVectorsWanted(), EPSGetEigenvectorLeft()

Location: src/eps/interface/opts.c
Index of all EPS routines
Table of Contents for all manual pages
Index of all manual pages

### Examples

src/eps/examples/tutorials/ex12.c.html