Re: Lining up the axes of multiplots/subplots

[Matthias Brennwald]

On 19.11.2006, at 19:38, John W. Eaton wrote:

> On 19-Nov-2006, Matthias Brennwald wrote:
>
> | Yes, it IS a gnuplot problem, and it's not that difficult to solve
> | (see my previous post). BUT: what is the clean method to talk to
> | gnuplot from Octave? I believe the internal __gnutplot_XYZ__  
> commands
> | are not intended to be used directly by 'normal' users, right?
>
> Right.  In the future, mixing higher-level plotting commands and
> sending commands directly to gnuplot will have even more unpredictible
> results than they do now.  For some background, please read
>
>   http://www.cae.wisc.edu/pipermail/octave-maintainers/2006- 
> November/001299.html
>   http://www.cae.wisc.edu/pipermail/octave-maintainers/2006- 
> November/001301.html
>
> in particular, the last paragraph of the first message, in which I  
> said
>
>   Until we have a fairly complete set of object graphics properties
>   available, we will just have to tell people that if they want full
>   control over graphics, they will need to write their data to a file
>   and use their favorite plotting package to generate the plots.  This
>   has really always been the case.  It's unfortunate that Octave ever
>   had the gplot and gset commands that made it appear that complete
>   control over gnuplot was possible (it never was).

Hmm, then maybe a corresponding note should be added to the help text  
of the __gnuplot_XYZ__ commands. All I get is:

------------------------
help __gnuplot_raw__
__gnuplot_raw__ is a built-in function

-- Built-in Function:  __gnuplot_raw__ (STRING)
     Send STRING directly to gnuplot subprocess.
------------------------

From this, I'd never guess that I shouldn't be using __gnuplot_raw__  
et al. And once I've built my code around the __gnuplot_XYZ__  
commands  (and once Octave has object graphics like Matlab) I'd be  
just 'a little bit surprised' that I can start over with my work.

> We will probably make it easier to communicate directly with gnuplot
> by allowing you to do the things that are outlined in the second
> message linked above, but you will have to assume complete
> responsibility of the plot as mixing arbitrary calls to
> __gnuplot_raw__ with the higher-level plotting commands will not
> work.  Given that, I wonder why one would not simply write out data
> files and then run gnuplot separately.

There are several reasons for that:
1. If I can use Octave to plot my stuff, I will (just because I can).
2. I have some code that was written for Matlab originally. This  
stuff includes plotting commands, and I want to run it in Octave.
3. I'm trying hard to make my code compatible with both Matlab and  
Octave (this allows more people to use my code). And my programs rely  
on plotting data. And sometimes I can't stand the fact that I can't  
do everything in Octave using the 'standard' Matlab-like commands. I  
therefore add __gnuplot_raw__ commands that are executed if my code  
is executed with Octave.

Apart from these points I have to admit that I love Matlab for its  
plotting functionality. In fact, at the beginning of my PhD work I  
decided to stick to gnuplot, because I wouldn't get 'locked in' to a  
commercial product that might suddenly stop to keep up with the  
computer world, or might even stop to exist out of the blue. While it  
seems to me that gnuplot can plot basically anything, I realised that  
am not intelligent enough to find out how to do it (or that it takes  
days or weeks to find out). Since I did most of my data processing in  
Matlab, I got used to the Matlab plotting, and I have to admit that I  
love it. I therefore switched from gnuplot to Matlab as my main  
plotting tool.

In conclusion, I prefer Matlab over Octave when it comes to plotting.  
Also, if I want to make my programs run under Octave AND Matlab, the  
current plotting functionality of Octave can pose problems. I'd  
therefore greatly appreciate (a subset) of Matlab's object-oriented  
plotting interface in Octave. After surfing the web a bit, I found  
some seemingly great stuff here:

http://wiki.octave.org/wiki.pl?ObjectGraphics

However, I am unsure whether this is just a wish list or if it is a  
description for some real-world code that allows Octave to plot in  
the Matlab way. Therefore:

A. How/where can I get this stuff (I couldn't find it on the above  
link)?
B. Can I help in any way to build/extend the Matlabish plotting  
functionality? How?

Cheers,
Matthias


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Matthias Brennwald
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