I have been using matplotlib a few days now and think I it is
> great but recently I have gotten hung up on a problem
> plotting negative numbers.
> I am trying to plot data where the y values are all negative.
> When I do this I get the No positive data to plot error. I
> have tracked it down to the following two line is
> /matplotlib/ticker.py: if minpos<=0: raise RuntimeError('No
> positive data to plot')
This should only be occurring if you have log scaling set. Could you
get a fresh copy of matplotlib CVS and see if you can replicate the
bug. And if so, please post a script that exposes it.