From: Darren Dale <dd55@co...>  20040812 14:16:56

Hi All, My research group submitted a paper for publication in a journal, and one of the requested changes was having the tickmarks formatted like $1x10^{4}$ (for the latexers out there) rather than 1e4, which was considered an unnecessary use of mathematical jargon. I wasn't the lead author on this particular paper, and therefore the plots were not created using Python and MPL. But I think this is a pretty standard formatting requirement in the scientific community. Would the creators of Matplotlib consider an option to format the ticks like this (does this capability exist and I havent found it yet)? In Matlab, when the tick labels require scientific notation, only the decimal component is listed in each tick label, and the exponential part is printed at the end of the axis. In Igor, the exponential part can be included in the yaxis label. Finally, one problem with formatting tick labels is how to deal with data spanning small ranges, but with large offsets, like array(range(10))+1e10. Maybe there is an interest in removing the offset from each tick label, and including it elsewhere in the figure? Then again, maybe that's getting too complicated. Is this attractive to the Matplotlib Gurus and Users? If so, is it something I could work on, or would it be best left to the masters? Darren 
From: John Hunter <jdhunter@ac...>  20040812 15:19:45

>>>>> "Darren" == Darren Dale <dd55@...> writes: Darren> Hi All, My research group submitted a paper for Darren> publication in a journal, and one of the requested changes Darren> was having the tickmarks formatted like $1x10^{4}$ (for Darren> the latexers out there) rather than 1e4, which was Darren> considered an unnecessary use of mathematical jargon. I Darren> wasn't the lead author on this particular paper, and Darren> therefore the plots were not created using Python and Darren> MPL. But I think this is a pretty standard formatting Darren> requirement in the scientific community. Would the Darren> creators of Matplotlib consider an option to format the Darren> ticks like this (does this capability exist and I havent Darren> found it yet)? Yes, this would be nice. Of course, you can manually format the ticks using mathtext, eg, from matplotlib.matlab import * rc('tick', labelsize=15) a=[8E8,10E8, 15E8] plot(a,a) ticks = arange(8,16) labels = ['$%d^{8}$'%val for val in ticks] set(gca(), xticks=ticks*1e8, yticks=ticks*1e8, xticklabels=labels, yticklabels=labels) show() but it would be nice to provide some automatic facilities for this. Darren> In Matlab, when the tick labels require scientific Darren> notation, only the decimal component is listed in each Darren> tick label, and the exponential part is printed at the end Darren> of the axis. In Igor, the exponential part can be included Darren> in the yaxis label. Finally, one problem with formatting Darren> tick labels is how to deal with data spanning small Darren> ranges, but with large offsets, like Darren> array(range(10))+1e10. Maybe there is an interest in Darren> removing the offset from each tick label, and including it Darren> elsewhere in the figure? Then again, maybe that's getting Darren> too complicated. This would definitely be a nice feature. It would require a little architectural change in the formatter. Basically the formatter would need to provide an additional method, eg get_offset, which would return None (the current default) or a string like '$10^{23}$. The axis, which calls the formatter, could check this value, and if not None, render it to the proper place (eg left of x axis). I could help you with this part. Below I'll include a script example showing how to plot a tick offset which you can currently use for figures. Basically, we'd just want to automate something along these lines. Darren> Is this attractive to the Matplotlib Gurus and Users? If Darren> so, is it something I could work on, or would it be best Darren> left to the masters? There's only one path to becoming a master, of course, which is to dive in. It would be great if you work on this. Getting ticking right is pretty hard since there are so many pathological cases out there. But it looks like you work with that kind of data so you'll be in a good position to find and fix the problem spots. I think you should take two approaches: 1) clean up the existing Locators and Formatters when you find bugs and 2) define some new ones. It shouldn't be too hard to define a new formatter that does the mathtext formatting for exponential ticking you've alluded to above. The only (minor) downside to doing mathtext formatting is that the font is likely different than nonmathtext on your figure. There are two ways to solve this: use the cmr font as the default for the entire figure or better, support mathtext layout (super/subscripting) for any font. Right now we use the computer modern fonts for mathtext because they have all the symbols, but there is no reason (other than time) that we can't use the mathtext layout algorithms for super/subscripting of non symbol fonts. Let me know how I can help... JDH # use an exponential tick offset from matplotlib.matlab import * rc('tick', labelsize=12) a=[8E8,10E8, 15E8] plot(a,a) ticks = arange(8,16) labels = ['%d'%val for val in ticks] # place the offset in axes coords t = text(.075, .075, r'$10^{8}\times$', transform=gca().transAxes, fontsize=14) t.set_clip_on(False) set(gca(), xticks=ticks*1e8, yticks=ticks*1e8, xticklabels=labels, yticklabels=labels) show() 