Re: Matrix regression of distnce matrices + non negative least square

[Jaroslav Hajek]

On Thu, Sep 10, 2009 at 4:57 PM, Corrado <address@hidden> wrote:
> Dear Jaroslav, Octave list,
>
> here I am again ....
>
> How do you calculate distance or dissimilarity matrices in Octave?

For instance, see
http://octave.sourceforge.net/doc/f/pdist.html

> and how do
> you treat triangular matrices + diagonal in Octave?  is there a separate
> package?
>

That depends. Diagonal matrices are a special type.
Triangular/symmetric matrices are typically treated as full, with
certain functions (such as matrix division) able to specialize. Of
course, you can also work with vectors of the upper/lower triangular
elements, or even with "jagged arrays" - cell arrays of vectors. Your
choice.

There's also a package for triangular matrices in OctaveForge's
extra/, but I don't think it's much used.

hth
-- 
RNDr. Jaroslav Hajek
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz