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# EPSSetProblemType

Specifies the type of the eigenvalue problem.

## Synopsis

    #include "slepceps.h"
    PetscErrorCode EPSSetProblemType(EPS eps,EPSProblemType type)

Logically Collective

## Input Parameters

- eps - the linear eigensolver context

- type - a known type of eigenvalue problem

## Options Database Keys

- -eps_hermitian - Hermitian eigenvalue problem

- -eps_gen_hermitian - generalized Hermitian eigenvalue problem

- -eps_non_hermitian - non-Hermitian eigenvalue problem

- -eps_gen_non_hermitian - generalized non-Hermitian eigenvalue problem

- -eps_pos_gen_non_hermitian - generalized non-Hermitian eigenvalue problem with positive semi-definite \(B\)

- -eps_gen_indefinite - generalized Hermitian-indefinite eigenvalue problem

- -eps_bse - structured Bethe-Salpeter eigenvalue problem

- -eps_hamiltonian - structured Hamiltonian eigenvalue problem

## Notes

This function must be used to instruct SLEPc to exploit symmetry or other kind of structure. If no problem type is specified, by default a non-Hermitian problem is assumed (either standard or generalized). If the user knows that the problem is Hermitian (i.e., \(A=A^*\)) or generalized Hermitian (i.e., \(A=A^*\), \(B=B^*\), and \(B\) positive definite) then it is recommended to set the problem type so that the eigensolver can exploit these properties.

If the user does not call this function, the solver will use a reasonable guess.

For structured problem types such as `EPS_BSE`, the matrices passed in via `EPSSetOperators()` must have been created with the corresponding helper function, i.e., `MatCreateBSE()`.

## See Also

EPS: Eigenvalue Problem Solver, `EPSSetOperators()`, `EPSSetType()`, `EPSGetProblemType()`, `EPSProblemType`

## Level

intermediate

## Location

src/eps/interface/epsopts.c

## Examples

src/eps/tutorials/ex24.c
src/eps/tutorials/ex46.c
src/eps/tutorials/ex56.c
src/eps/tutorials/ex5.c
src/eps/tutorials/ex2.c
src/eps/tutorials/ex41.c
src/eps/tutorials/ex18.c
src/eps/tutorials/ex29.c
src/eps/tutorials/ex12.c
src/eps/tutorials/ex1.c

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