Re: [matplotlib-devel] New backend API

[Darren D. <dd...@co...>]

On Monday 20 March 2006 11:05, John Hunter wrote:
> I ran a test script to profile this before and after, making marker
> plots of various sizes.  I think you'll be happy with the fruits of
> your labors.  Because we save the effort of setting a gc for each
> marker, and thus avoid of lot of redundant function calling and state
> setting in the output file, the results are much better in time and space
>
>     import time, os
>     from pylab import figure, close, nx
>
>     for i in 10,100,1000,10000,100000:
>         fig = figure(1)
>         ax = fig.add_subplot(111)
>         x,y = nx.mlab.rand(2,i)
>         tnow = time.time()
>         ax.plot(x,y, 'o')
>         fname = 'file%d.ps'
>         fig.savefig(fname)
>         elapsed = time.time() - tnow
>         fsize = os.stat(fname)[6]
>         print 'i=%06d  time= %1.2fs  size=%1.1fkb'%(i, elapsed, fsize/1e3)
>         close(1)
>
> Old API:
>     > python test.py
>
>     i=000010  time= 0.33s   size=142.4kb
>     i=000100  time= 0.30s   size=154.9kb
>     i=001000  time= 0.43s   size=284.1kb
>     i=010000  time= 1.79s   size=1575.9kb
>     i=100000  time= 15.37s  size=14495.6kb
>
> New API:
>     > python test.py
>
>     i=000010  time= 0.53s  size=148.1kb
>     i=000100  time= 0.29s  size=146.5kb
>     i=001000  time= 0.30s  size=163.6kb
>     i=010000  time= 0.44s  size=334.5kb
>     i=100000  time= 2.17s  size=2044.5kb
>
> So for largish marker plots, you have about a 7x improvement in speed
> and filesize.  You may want to use this script to profile and see if
> you can't eke out some extra gains.  Maybe another 2x <wink>.  This is
> using the default rc file.
>
> Now that we have a good implementation in a pure python backend that
> others can follow as an example, I will shortly deprecate the old API
> entirely and begin pruning the redundant methods.  Considering that
> both your changes and Eric's are significant enhancements, we may wait
> to do this until one release cycle down the road, so that we don't
> delay getting these out to the wider community.

I just committed a fix for a minor bug, it didnt effect the performance. My 
results are comparable to yours. How's this for a performance boost: set 
ps.useafm : true in rc:

Old API:
i=000010 time= 0.09s size=6.2kb
i=000100 time= 0.07s size=18.0kb
i=001000 time= 0.19s size=147.2kb
i=010000 time= 1.43s size=1439.2kb
i=100000 time= 13.99s size=14358.6kb

New API:
i=000010 time= 0.16s size=11.7kb
i=000100 time= 0.07s size=9.6kb
i=001000 time= 0.06s size=26.7kb
i=010000 time= 0.13s size=197.7kb
i=100000 time= 0.75s size=1907.7kb

I dont see where I can make things any faster in draw_markers, we trimmed all 
the fat when we started on this a year ago.

Here's a bug: I need isnan to create my mask. It is provided by numerix with 
numpy and numarray, but not Numeric. Can this be rectified?

Darren