Re: Slow plotting (redraw due to legend?)

[Mike Miller]

On Thu, Mar 17, 2016 at 08:45:55 +0000, address@hidden wrote:
> In the meantime some people posted some test results in another thread:
> 
> http://lists.gnu.org/archive/html/help-octave/2016-03/msg00166.html
> http://lists.gnu.org/archive/html/help-octave/2016-03/msg00187.html
> http://lists.gnu.org/archive/html/help-octave/2016-03/msg00188.html
> 
> Number of calls matches my tests, execution time is comparable.
> However, noone tested 3.2.x or plotting without changing the legend,
> which points to the real problem (I think there are two kinds of
> regression from 3.2.x to later versions, no matter whether it is on
> linux or windows).

I don't think what you're calling a regression is simply loss of
performance for no good reason. I believe that legend has a lot more
functionality than it used to. Functionality that you may not need, but
that is required for Matlab compatibility. And that may be most of what
is making legend slower in newer versions.

Note that legend is an m-file function, so it should be easy for anyone
familiar with Octave to inspect and debug it. Also compare the "fast"
legend.m from 3.2.4 (134 lines) to 4.0.0 (1140 lines):

http://hg.savannah.gnu.org/hgweb/octave/file/release-3-2-4/scripts/plot/legend.m
http://hg.savannah.gnu.org/hgweb/octave/file/release-4-0-0/scripts/plot/appearance/legend.m

It sounds like you are very interested in this performance loss. If that
translates into a willingness to help improve the function, please do
file a bug report and start investigating what some of the critical
bottlenecks in the legend function are.

-- 
mike