Re: plot matrix?

[Ethan M. <merritt@u.washington.edu>]

On Saturday 21 November 2009, Philipp K. Janert wrote:
> On Saturday 21 November 2009 07:54:55 pm you wrote:

> > >
> > > For plot (not splot), I am completely confused. Does
> > > it even make sense to have the notion of a "matrix"
> > > format for plot? The "matrix" keyword seems to suggest
> > > that the data is on a regular, 2-dim grid. This notion
> > > does not seem to have any meaning for plot.
> >
> > It is clearly useful to have such a capability.
> > I use it to make heat maps, for instance.
> > See heatmaps.dem
> 
> But that just goes to my point: the examples in 
> heatmaps.dem all use splot (not plot), except
> for one that uses "with image", which I think is
> for a binary file (not ascii).

The one in the demo is in-line ascii data.

But hmm, you're right that it doesn't include the 'matrix' keyword.
Oh... I see. That's the wrong demo.  I was thinking of the
heatmaps in imageNaN.dem, which are drawn like this:

plot '-' matrix with image failsafe
0    5 4 3 1 0
?    2 2 0 0 1
Junk 1 2 3 4 5
NaN  0 0 3 1 0
Inf  3 2 0 2 3
-Inf 0 1 2 4 3
e
e

> I still can't see any "proper" use for an ASCII
> matrix with plot (not splot).

The end result I was aiming for when last I looked at this was
to generate heatmaps directly from a csv file (e.g. from excel),
where the row and column categories had headers.  I'll draw this
here as in-line data with whitespace.   The command below doesn't
work, of course, but I was trying to understand the whole matrix
mechanism well enough to see if I could tweak things to make it work:

plot "-" matrix using xticlabels(0):yticlabels(0) with image
  xx  A   B   C
   X  0   2   1
   Y  2   0   1
   Z  1   1   2 

I forget now why I wanted it to be a 'plot' command rather than 'splot'.
Maybe because of the limited control over tic label placement in 3D.
Or maybe because the code at first looked slightly less confusing.

	EAM