petsc-3.14.6 2021-03-30

KSPGMRESModifiedGramSchmidtOrthogonalization

This is the basic orthogonalization routine using modified Gram-Schmidt.

PetscErrorCode  KSPGMRESModifiedGramSchmidtOrthogonalization(KSP ksp,PetscInt it)

Collective on ksp

	ksp	- KSP object, must be associated with GMRES, FGMRES, or LGMRES Krylov method
	its	- one less then the current GMRES restart iteration, i.e. the size of the Krylov space

-ksp_gmres_modifiedgramschmidt

- Activates KSPGMRESModifiedGramSchmidtOrthogonalization()

In general this is much slower than KSPGMRESClassicalGramSchmidtOrthogonalization() but has better stability properties.

intermediate