Re: no way for simple matrix lookup ?

[Mike Miller]

On Wed, 16 Jun 2004, D. Goel wrote:

> The following message is a courtesy copy of an article that has been 
> posted to gmane.comp.gnu.octave.general as well.
>
> Mike, that doesn't work, your recipe below is the first thing I tried.
>
> Example, A = [1 3; 2 4]
> b=c=[1 2].
>
> The answer needed is [1 4], but both of your answers below give me
> [1 2 3 4].


It works like this:  In your example, A(b,c) tells Octave to extract from 
matrix 'A' the rows given by 'b' and the colums given by 'c'.  Both 'b' 
and 'c' equal [1,2], so Octave extracts rows 1 and 2 and columns 1 and 2 
from matrix 'A'.

Now I think I understand you.  You want A(1,1) and A(2,2).  Strangely, I 
wsa trying to do that yesterday(!) and failed.  I hope someone will tell 
you what you need to do because I also need to know.

Mike

--
Michael B. Miller, Ph.D.
Assistant Professor
Division of Epidemiology
and Institute of Human Genetics
University of Minnesota
http://taxa.epi.umn.edu/~mbmiller/



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