Re: with parallelaxes dumps core

[Daniel J S. <dan...@ie...>]

On 01/27/2015 10:25 AM, Philipp K. Janert wrote:
> On Tue, 27 Jan 2015 03:06:16 -0600
> Daniel J Sebald<dan...@ie...>  wrote:
>
>> On 01/26/2015 10:38 PM, sfeam wrote:
>>> On Monday, 26 January 2015 07:28:19 PM Philipp K. Janert wrote:
>>>>
>>>> The new plot style "with parallelaxes"
>>>> is cute. Unfortunately, it also dumps
>>>> core - whenever there are more than 7
>>>> columns to plot.
>>>
>>> The maximum is set at compile time, but
>>> yes the default is 7.
>>>
>
> Daniel -
>
> Thanks for looking into this!
>
> One comment, though: before going down this
> path (of extending the permissible number of
> cols in "using") very far, let's consider
> whether this is the right way to do it.
>
> Already, entering 7 explicit col numbers is a
> pain. Entering 35 (or whatever) different ones
> is simply not practical.

Well, as with binary data, it could be that the data file and the 
command itself are constructed by automation, i.e., a computer program 
or script.  Plus, it isn't that difficult to build up a long command in 
an input file using an editor.


> Should the whole approach be rethought? Is
> "plot" even the right command? I'd argue (not
> having looked at the implementation) that we
> should consider "splot", because splot naturally
> deals with data on a rectangular grid (matrix data).

I'm not sure a rectangular grid is any type of requisite.  From the 
documentation, it sounds like the parallelaxes is a means to visually 
show correlation between disparate measurements.  That is, if there are 
strong color bands, I assume that is more correlation, be it positive or 
negative.


> And that's exactly the type of data used for
> parallel axes plots. Put another way: splot
> already handles dynamic rows AND columns.

It actually may be its own type of plot, neither "plot" nor "splot". 
 From what Ethan describes, I'm guessing that the data file is re-read 
once for each axis to get the column of data that is to appear on the 
axis.  In some sense it's a one-dimensional plot, isn't it?  That is, 
the data only appears on one axis only and it is simply that there are 
many axes.  So, some analogous terms might be:

plot   ->  plot2d
splot  ->  plot3d
paxis  ->  plot1d

We can think of plot2d being a subset of plot3d, with a viewing angle 
that's orthographic.  We can think of plot1d as being a subset of 
plot2d, again with a viewing angle that eliminates one of the 
dimensions.  But parallel axes is some kind of new creature, basically 
connecting points across multiple plots.  In theory it could be done 
with 2d and 3d plots, but would be a mess to look at of course.  So, 
parallelaxis is more along the lines of "multiplot", isn't it?  Should 
it's syntax fall more along that lines?  E.g.,

set parallelaxis layout 7,1

Dan