On 05/25/2012 12:46 PM, Dan Drake wrote:
> Hello matplotlib developers,
>
> In Sage, we've run into a problem with plotting a sequence whose
> y-values change by very small amounts. Here's an example that doesn't
> use anything from Sage:
>
> import pylab
> pylab.plot([0, 1], [0, 1e-14])
> pylab.savefig("works.png")
> pylab.close()
> pylab.plot([0, 1], [1, 1+1e-14])
> pylab.savefig("fails.png")
> pylab.close()
>
> We're using matplotlib 1.1. Here's a trac ticket where we are working on
> this: http://trac.sagemath.org/sage_trac/ticket/11973. One of our
> developers suspects matplotlib.ticker.MaxNLocator.bin_boundaries but we
> don't really know.Dan, It is easy enough to remove the immediate roadblock in scale_range, but that just opens up a can of floating point worms. The axis spines start getting misplaced, for example, as the range being plotted gets too small relative to the offset. Straightening all this out, or even substantially improving it, is potentially tricky. To the extent that it can be done, it will have to be in master, which already includes one cleanup of a floating point kluge. Note that part of the problem here is that in your example we are running out of precision. The best way to handle it is to subtract an offset first, and just plot the deviation from that offset. I think this is best done at the application level. We can probably make mpl's handling of the problem degrade more gracefully, however, than it does at present. Eric > > Thanks for any help or comments! > > Dan > > -- > --- Dan Drake > ----- http://mathsci.kaist.ac.kr/~drakes > ------- ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
