Re: [matplotlib-devel] NaN support

[Eric F. <ef...@ha...>]

Darren Dale wrote:
> It looks like the new transforms codebase does not support data that contains 
> NaNs the way the old trunk did:
> 
> plot([1,2,NaN,4,5]) produces a plot with no line break
> plot([NaN,2,3,4,5]) produces a plot with no line
> 
> I know use of NaN's is not encouraged, and we have discussed it on this list. 
> But since they are sometimes unintended and unavoidable, I'm reporting the 
> behavior so people are not surprised when they get an empty plot.
> 
> Darren

This comes up often enough that it might be worth doing automatic 
masking of NaNs in the high-level argument processing wherever we are 
now doing x=npy.ma.asarray(x) or similar.  The calls could be replaced 
with x=npy.ma.masked_where(~npy.isfinite(x),x) I have resisted adding 
this overhead, but now I think the overhead might be negligible in 
almost all cases.  It looks like it would be on the order of 
milliseconds per high-level call, where by high-level call I mean plot, 
pcolor, quiver, etc. (either via pylab or Axes method).

Eric