Re: [matplotlib-devel] performance (speed) of logarithmic plots

[Gökhan S. <gok...@gm...>]

On Thu, Mar 18, 2010 at 6:21 PM, Andrew Hawryluk <HA...@no...>wrote:

> I've observed a significant difference in the time required by different
> plotting functions. With a plot of 5000 random data points (all
> positive, non-zero), plt.semilogx takes 3.5 times as long as plt.plot.
> (Data for the case of saving to PDF, ratio changes to about 3.1 for PNG
> on my machine.)
>
> I used cProfile (script attached) and found several significant
> differences between the profiles of each plotting command. On my first
> analysis, it appears that most of the difference is due to increased use
> of mathtext in semilogx:
>
>                                ==================================
>                                Plotting command
> ==================================================================
> cumtime (s)                     plot    semilogx  semilogy  loglog
> ==================================================================
> total running time              0.618   2.192     0.953     1.362
> axis.py:181(draw)               0.118   1.500     0.412     0.569
> text.py:504(draw)               0.056   1.353     0.290     0.287
> mathtext.py:2765(__init__)      0.000   1.018     0.104     0.103
> mathtext.py:2772(parse)         ---     1.294     0.143     0.254
> pyparsing.py:1018(parseString)  ---     0.215     0.216     0.221
> pyparsing.py:3129(oneOf)        ---     0.991     ---       ---
> pyparsing.py:3147(<lambda>)     ---     0.358     ---       ---
> lines.py:918(_draw_solid)       0.243   0.358     0.234     0.352
> =================================================================
>
> It seems that semilogx could be made as fast as semilogy since they have
> to do the same amount of work, but I'm not sure where the differences
> lie. Can anyone suggest where I should look first?
>
> Much thanks,
>
> Andrew Hawryluk
>
> matplotlib.__version__ = '0.99.1'
> Windows XP Professional
> Version 2002, Service Pack 3
> Intel Pentium 4 CPU 3.00 GHz, 2.99 GHz, 0.99 GB of RAM
>
>
>
Hello,

How did you get the cumtime listing? The output of the run doesn't produce a
cumulative sum table as you showed here.

================================================================================
Platform     :
Linux-2.6.31.9-174.fc12.i686.PAE-i686-with-fedora-12-Constantine
Python       : ('CPython', 'tags/r262', '71600')
NumPy        : 1.5.0.dev8038
Matplotlib   : 1.0.svn
================================================================================



-- 
Gökhan