[Rd] Computer algebra in R - would that be an idea??

[Gabor Grothendieck]

On 7/15/05, simon blomberg <blomsp at ozemail.com.au> wrote:
> > >  >>>>> "bry" == bry  <bry at xdocs.dk>
> > >>>>>>      on Fri, 15 Jul 2005 14:16:46 +0200 writes:
> > >
> > >     bry> About a year ago there was a discussion about interfacing R
> > >with J on the J
> > >     bry> forum, the best method seemed to be that outlined in this
> > >vector article
> > >     bry> http://www.vector.org.uk/archive/v194/finn194.htm
> > >
> > >(which is interesting to see for me,
> > >  if I had known that my posted functions would make it to an APL
> > >  workshop...
> > >  BTW: Does one need special plugins / fonts to properly view
> > >      the APL symbols ? )
> > >
> > >
> > >     bry> and use J instead of APL
> > >
> > >     bry> http://www.jsoftware.com
> > >
> > >well, I've learned about J as the ASCII-variant of APL, and APL
> > >used to be my first `beloved' computer language (in high school!)
> > >-- but does J really provide computer algebra in the sense of
> > >Maxima , Maple or yacas... ??
> >
> > I wonder if at this point it would be useful to think about how a
> > symbolic algebra system might be used by R users, and whether that
> > would affect the choice of system. For example, Maxima and yacas seem
> > to be mostly concerned with "getting the job done", which might be
> > all that the data analyst or occasional user needs. However,
> > mathematical statisticians might be more concerned with developing
> > new mathematics. For example, commutative algebra has been found to
> > be very useful in the theory of experimental design (e.g. Pistone,
> > Riccomagno, Wynn (2000) Algebraic Statistics: Computational
> > Commutative Algebra in Statistics. Chapman & Hall). Now, Maxima can
> > already do the necessary calculations (ie Groebner bases of
> > polynomials), but as far as I know, yacas cannot. But who knows where
> 

yacas does have the Groebner function, e.g.
 
In> Groebner({x*(y-1),y*(x-1)})
Out> {x*y-x,x*y-y,y-x,y^2-y};