Hi plplot folks: There has been a conversation on the PDL list recently about which plotting package to use by default for PDL. I've been advocating for use of PLplot, but have limited time to spend on interface development.

One of the major perceived limitations of PLplot is image plotting speed. Apparently PLplot uses an expensive algorithm to contour data.

A nice performance plot showing the problem is attached.

Does any of you know about this? Is there a way to speed up image plotting?

Thanks much,

  Doug Hunt

dh...@ucar.edu
Software Engineer
UCAR - COSMIC, Tel. (303) 497-2611

---------- Forwarded message ----------
Date: Tue, 5 Mar 2013 10:43:10 -0700
From: Craig DeForest <defor...@boulder.swri.edu>
To: dh...@ucar.edu
Cc: Craig DeForest <defor...@boulder.swri.edu>,
    Karl Glazebrook <karlglazebr...@mac.com>,
    perldl list <per...@jach.hawaii.edu>
Subject: Re: [Perldl] A common, working plotting package?

Funny you should mention that -- there's a Mac Port of PLplot now, and it installed flawlessly when I tried it last night -- which is a huge change from my earlier experience. It is indeed a very nice plotting package - the high level plots, in particular, are very nice looking.

Derek has had difficulty using it for image plotting, largely because it uses a very expensive algorithm that is best adapted to low resolution data (and does a fabulous job in that case) but does not scale well to high resolution images. The difficulty is best summed up in the performance plot (apropos to the performance discussion last night). I don't know if there's a better way than the existing high-level contour plot method. As far as point-plotting speed, it's about the same as gnuplot. The plot times are on a 2011 MacBook Pro with stock Ports install.




On Mar 5, 2013, at 10:03 AM, Doug Hunt <dh...@ucar.edu> wrote:

Hi Karl:  I still maintain that PLplot is a good, modern plotting package that 
runs on all required platforms.  It is well maintained and has a nice build 
system.  It also has interactive capabilities which I don't know much about.

I have not supported Windows and Mac with PDL::Graphics::PLplot because I don't 
have the time and access to required machines.

I think others who have time/machines could do this without much effort.

I think PLplot could be brought up to speed with minor enhancements to 
PDL::Graphics::PLplot, which I don't necessarily have time to do.

Regards,

 Doug

dh...@ucar.edu
Software Engineer
UCAR - COSMIC, Tel. (303) 497-2611

On Tue, 5 Mar 2013, Karl Glazebrook wrote:

If GNUplot can plot a million points or a 4096^2 image with a delay < 1s and no 
memory disaster then that would be fast enough for me.

I wish there was a better solution

Karl



On 04/03/2013, at 2:04 AM, Henning Glawe wrote:

On Sun, Mar 03, 2013 at 10:04:45PM +1100, Karl Glazebrook wrote:
I don't know how 'modern' PLplot is. The documentation still talks about 
Tektronix terminals!

I did some googling, DISLIN seemed the closest but is only semi-frree.

In astronomy people really only use pgplot at the c/f77 level. (At a higher 
level they use language specific graphics, e.g. IDL, IRAF, Python, sm (!), 
gnuplot, MMA).

What about other scientific fields? What do people you know use?

In my field (computational quantum physics/chemistry), computation and
visualization are usually treated separately. Typically, the actual
numerical simulations are very heavy (taking CPU-days or even CPU-weeks on
current HPC-Clusters).
The visualization is performed in a separate step, where different "classes"
of tools are employed:
* Special purpuse tools for molecule/crystal visualization, which show:
- crystal structures
- densities either on cutting planes or as equipotential surfaces
Tools belonging to this class are:
- xcrysden http://www.xcrysden.org/
- v-sim    http://www-drfmc.cea.fr/L_Sim/V_Sim/index.en.html
* General-purpose plotting tools with a focus on 2D-visualization:
- gnuplot  http://gnuplot.sourceforge.net/
- grace    http://plasma-gate.weizmann.ac.il/Grace/
* General-purpose plotting tools with more focus on 3D-visualization:
- OpenDX   http://en.wikipedia.org/wiki/IBM_OpenDX
  (Official website seems to be down)
  Learning curve is quite steep, interface is a bit awkward to use (for
  modern standards)
- paraview http://www.paraview.org/
  Easier to use than OpenDX; very powerful visualization tool, integrated
  python scripting support for
  - sources (data generation)
  - filters (data processing)
  - general-purpose macros

Looks dismal. Perhaps the moral is people who put significant effort in to 
visuals tend to go commercial?

I don't think so. You can get quite good results out of free
visualization tools, altough sometimes you may have to tweak the settings a
bit. One very good example for this is gnuplot; the default settings have not
changed much in the past 20 years (think backwards compatibility), but with
some modifications in your gnuplot scripts, plots may look a lot more
attractive. This is one of the websites showing how to do this:
http://www.gnuplotting.org

For paraview, there are some good examples in the image gallery:
http://www.paraview.org/paraview/project/imagegallery.php


Maybe we have to go back to the question what _kind_ of visualization support
we need to have available directly within PDL.

In my opinion, a very simple plotting interface used mainly for
debugging/development is enough.
For anything beyond this, there are really good plotting tools available also
as free software, we just need to be able to export data in a format readable
by them.

--
c u
henning



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