Matrix in R

but if in my function 
pp_ris2[i,j]=myfunction}
must be the indexes 0-0,0-1,0-2,0-3, ....?

You'll have to take care of that yourself with a bit of index
arithmetics. It's  the same you encounter in C, if you are
modelling something that would like to be indexed starting with 1 -
just the other way round.

cu
	Philipp

Dr. Philipp Pagel
Lehrstuhl f?r Genomorientierte Bioinformatik
Technische Universit?t M?nchen
Wissenschaftszentrum Weihenstephan
Maximus-von-Imhof-Forum 3
85354 Freising, Germany
http://webclu.bio.wzw.tum.de/~pagel/