Re: [Matplotlib-users] Scatter plots and GTK backend

[Dominique O. <do...@da...>]

* On Mon, 01 Mar 2004, John Hunter wrote:

> It looks like there is a "print" statement somewhere in your code.
> It's possible that this was from a vestigial debug command I left in.
> I don't get get it on my system.  Are you using matplotlib-0.50?  I
> also don't get the "None Active" line.

I am in Windows 2000 and XP. I am using 0.50e in Linux, because i am
upgrading my gcc. The newer 0.50 won't compile with the gcc i have now.
I only get the 'None Active' in Linux though. I suspect it comes from
my GTK. I am using KDE and installing Gnome libraries when i need them.
There might be a glitch somewhere.
 
> I'm using this as a test script  
> 
>     from matplotlib.matlab import *
> 
>     x = 100*rand(100000)
>     y = 100*rand(100000)
>     s = rand(100000)
> 
>     scatter(x,y,s)
>     #plot(x,y,'o')
>     show()
> 
> Takes about 30s on my system.  Note that plot with circles can be must
> faster that scatter if you don't need to vary the size or color of the
> symbols.

I see that plot is usually faster than scatter. The script works fine
with smaller data sets, and takes a pretty long time with larger sets.
 
> There are several areas where matplotlib performance is subpar -
> mostly for large numbers of patches (circles for scatter, rectangles
> for pcolor).  Fixing this is a fairly high priority and I have a good
> idea how to go about it - see
> http://sourceforge.net/mailarchive/message.php?msg_id=7142332 for a
> recent discussion.  I think in the next 3-4 weeks I can get this
> fixed.  Basically, the plan is to set up an additional backend method
> or two that the various backends may optionally implement in extension
> code for performance.

That would be wonderful. I have never looked into the Gnuplot code but
they have a fairly efficient algorithm. Plotting data sets like that i
described takes less than a second on my laptop (from the Python
interface). It would be great if matplotlib could do it too.
 
> Are you using the default GTK that comes with SuSE or did you upgrade?
> I have gotten myself into a world of pain before trying to upgraded
> GTK libs on a linux box.  It does look like you are getting some
> unusual behavior.  Make sure you are using the latest matplotlib and
> try running the test script I posted above.  If you still get the same
> errors, something is whacked with your install or paths.  Otherwise,
> stay tuned for performance enhancements coming soon to theaters
> everywhere.

You can be sure i'm staying tuned.

Dominique