slepc-3.18.2 2023-01-26
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# EPSSetTwoSided

Sets the solver to use a two-sided variant so that left eigenvectors are also computed.

### Synopsis

    #include "slepceps.h"
    PetscErrorCode EPSSetTwoSided(EPS eps,PetscBool twosided)

Logically Collective on eps

### Input Parameters

| eps | - the eigensolver context
| twosided | - whether the two-sided variant is to be used or not

### Options Database Keys

| -eps_two_sided <boolean> | - Sets/resets the twosided flag

### Notes

If the user sets twosided=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.

When using two-sided solvers, the problem matrices must have both the MatMult and MatMultTranspose operations defined.

### See Also

EPSGetTwoSided(), EPSGetLeftEigenvector()

### Level

advanced

### Location

src/eps/interface/epsopts.c

### Examples

src/eps/tutorials/ex41.c.html
Index of all EPS routines
Table of Contents for all manual pages
Index of all manual pages