it seems that there are two minor bugs in matplotlib concerning the logspace function.
1) line 93 of mlab.py:
return exp(linspace(log(xmin), log(xmax),Nh))
- should be N or Nh in the both lines;
2) pylab does not import logspace at all:
line 293 of pylab.py:
from matplotlib.mlab import linspace, ...
- should be
from matplotlib.mlab import linspace, logspace, ...
I have just found matplotlib, and it seems to me that it is very good and promising product, albeit not yet as polished as octave/gnuplot pair. The mathtext feature which eliminates all hassles with psfrag is especially useful.