Dear gretl listers, hi from Paris, again ! Still on my demand system analysis, I need to apply the Delta method to compute standard errors of price and income elasticities. To do this I must access to numerical derivatives so that i can compute an approximation. I my reading is ok, it seems that numerical derivatives are accessible in the nls command. Is there another way to compute/show the jacobian from another model ? thanx a lot in advance cheers Franck