ErrorBarFunction question.

*To*: mathgroup at smc.vnet.net*Subject*: [mg12709] ErrorBarFunction question.*From*: Rob Smith <rob at groucho.med.jhmi.edu>*Date*: Wed, 3 Jun 1998 02:21:00 -0400*Sender*: owner-wri-mathgroup at wolfram.com

MathUsers: I am having trouble defining my own function for error bars in MultipleListPlot that I think is probably a pattern matching problem. Basically, I just want error bars without the horizontal lines (serifs) at each end of the bar. Without using ErrorBarFunction the plot comes out as expected. I have unsymmetrical error and, thus, have a list of the following form: {{0.28, 0.13}, ErrorBar[{-0.19, 0.32}]} ... ^ ^ ^ ^ x y negerr poserr So the corresponding error bar can be represented by a line from (x,y+negerr) to (x, y+poserr); note that negerr is negative, hence y+negerr. So I defined an error bar function as follows: barfunc[{x_, y_}, ErrorBar[{negerr_, poserr_}] := Line[{{x, y+negerr}, {x, y+poserr}}] And then included in the MultipleListPlot statement: ErrorBarFunction -> barfunc Obviously this doesn't work or you wouldn't be reading this! I've played the usual brace games and still can't get this to work. The error I get is: Unknown Graphics primitive barfunc[{0.28,0.13}, <<1>>] encountered. Does anybody know what I am doing wrong? Any help would be greatly appreciated. Thanks, Rob Smith Department of Biophysics & Biophysical Chemistry Johns Hopkins University School of Medicine 725 N. Wolfe St. Baltimore, MD 21205-2185