2D cluster of 2D matrix in Octave?

[Mark Wall]

Hello!

I would love to use Octave for the following 2 tasks, but am unable 
to determine if Octave will work.  My primary question- is this 
possible in Octave?  Secondary- if yes, how?

We routinely use MatLab with the Statistics Tool Box to manipulate 
and plot a 2 dimensional matrix (m x n) of real numbers.  If you 
think of each dimension as an array of vectors (e.g. a collection of 
m vectors (each n-dimensions), we 1) cluster these (and generate a 
dendrogram) for both dimensions as below using a city-block distance 
measure:

original matrix with labels
----------------
   W X Y Z
A  0 1 0 0
B  0 1 0 1
C  5 0 0 0
D  0 0 0 2
E  5 0 0 0

Clustered matrix
----------------
   W Y X Z
E  5 0 0 0
C  5 0 0 0
A  0 0 1 0
B  0 0 1 1
D  0 0 0 2

In reality, m and n are between 50 and 1000 so we 2) display these 
matrices as an x-y-color plot for easy visualization.  Think of this 
as a square frame with each pixel representing a matrix element.  The 
values are represented by a color continuum (dark blue = low values, 
through yellow to red = high values).  I can provide a JPEG if 
necessary.

With large matrices, we isolate sub-clusters by creating new matrices 
that are the appropriate slices of the original matrix and then 
repeat steps 1 and 2 on the sub-matrices.


Thank you,

Mark Wall
---------
HHMI/UT Southwestern Medical Center
5323 Harry Hines Blvd.
Dallas, Texas  75390-9050
USA
214.648.5050



-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------