id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
234	Discrepancy between minROPP and LevMarq minimisers	Ian Culverwell	Ian Culverwell	"ROPP5 testing has shown large differences in retrievals using these two minimisers (eg see #232). 

Huw Lewis documented similar differences (if not quite as bad) in GSR 6.

We should find out why minROPP and LevMarq differ. 

Here are some preliminary thoughts:

Plots of the convergence of both schemes (in terms of J and dx, the normalised change in the state from one iteration to the next) are listed below, for the 8 profiles in IT-1DVAR-03, for reference with Huw's earlier work in GSR-03 and GSR-06

== Refrac, J ==

"	defect	new	normal	6.0	ropp_1dvar	5.0		minropp levmarq minimisation