petsc-3.7.5 2017-01-01

SNESQNSetScaleType

Sets the scaling type for the inner inverse Jacobian in SNESQN.

#include "petscsnes.h" 
PetscErrorCode SNESQNSetScaleType(SNES snes, SNESQNScaleType stype)

Logically Collective on SNES

	snes	- the iterative context
	stype	- scale type

-snes_qn_scale_type <shanno,none,linesearch,jacobian> -

	SNES_QN_SCALE_NONE	- don't scale the problem
	SNES_QN_SCALE_SHANNO	- use shanno scaling
	SNES_QN_SCALE_LINESEARCH	- scale based upon line search lambda
	SNES_QN_SCALE_JACOBIAN	- scale by solving a linear system coming from the Jacobian you provided with SNESSetJacobian() computed at the first iteration of QN and at ever restart.

scaling type