hello..... Anyone? I would very much love to see this fixed, and I am ready to help out, but I do not know how to browse through the code. Despite the fact that log(errors) should of course not be used, but rathter errors/values/log(10), Michael's point still remains : values- errors in log scale can be negative, so that the artist should just draw a bar until the lower limit of the vertical bar. I would say that this is the standard practice. Sorry for my previous email beside the point. Johann
Cohen-Tanugi Johann wrote: > I tried to look at the code (axes.py I presume) in order to attempt a > patch, but it defeated me, I do not have the instructions to navigate > through this code :) > Where is the actual transform of the error bars occurring? > thanks, > Johann > > Michael Droettboom wrote: > >> I have to say I don't really have a lot of experience with error bars >> on log plots -- but the root cause here is that the lower bound of the >> error bar goes negative, and as we all know, the log of a negative >> number is undefined. If you can suggest where the lower bound should >> be drawn or provide third-party examples, I'm happy to look into this >> further and resolve this "surprise". >> >> Mike >> >> Cohen-Tanugi Johann wrote: >> >>> yes exactly.... >>> I should have provided a test case, thanks for following up! >>> Johann >>> >>> Matthias Michler wrote: >>> >>> >>>> Hello Johann, >>>> >>>> is the problem you are reporting the one I observe in the attached >>>> picture? Namely some vertical and horizontal lines are missing when >>>> using yscale="log". More precisely everything below y=1 seems to be >>>> missing. >>>> >>>> The picture was generated with the code below and >>>> matplotlib.__version__ = '0.98.6svn' >>>> matplotlib.__revision__ = '$Revision: 6887 $' >>>> >>>> best regards Matthias >>>> >>>> ############################### >>>> import numpy as np >>>> import matplotlib.pyplot as plt >>>> >>>> plt.subplot(111, xscale="log", yscale="log") >>>> x = 10.0**np.linspace(0.0, 2.0, 20) >>>> y = x**2.0 >>>> plt.errorbar(x, y, xerr=0.1*x, yerr=5.0+0.75*y) >>>> plt.show() >>>> ################################ >>>> On Friday 27 March 2009 16:12:12 Cohen-Tanugi Johann wrote: >>>> >>>> >>>>> Hello, what is the best way to get log log plots with error bars? I >>>>> tried putting log10() everywhere but as I was afraid results look >>>>> ugly.... >>>>> thanks, >>>>> johann >>>>> >>>>> ------------------------------------------------------------------------ >>>>> >>>>> >>>>> ------------------------------------------------------------------------ >>>>> >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> >>>>> >>>>> >>>>> ------------------------------------------------------------------------ >>>>> >>>>> >>>>> _______________________________________________ >>>>> Matplotlib-users mailing list >>>>> Matplotlib-users@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>>>> >>>>> >>> ------------------------------------------------------------------------------ >>> >>> >>> _______________________________________________ >>> Matplotlib-users mailing list >>> Matplotlib-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>> >>> > > ------------------------------------------------------------------------------ > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > ------------------------------------------------------------------------------ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
