Re: Constructing polynomials

[Karim Belabas <Karim.Belabas@math.u-psud.fr>]

* Justin Walker [2004-07-22 04:53]:
> I would like to construct a polynomial/series dynamically, ending up 
> with an "object" that I can evaluate, a la "f(1)", where 'f' is the 
> thing constructed.
> 
> I've looked through the doc and the archives (although it's hard to 
> know what to look for), and don't see any indication that it's 
> possible.
> 
> In psuedo-code terms, I'd like to do something like
> 
> MyProc(a,b)=
> {
>     f(x)=(x+a)^b;
>     for (i=1,limit, print(f(i)));
> }
> 
> Is this (a) feasible; (b) not easy; (c) Forgetaboutit?

Why not:

  MyProc(a,b)=
  {
    f=(x+a)^b;
    for (i=1,limit, print(subst(f, x, i)));
  }

? If you insist on defining a user function, then you can use

  MyProc(a,b)=
  {
    ( f(x) = (x+a)^b );
    for (i=1,limit, print(f(i)));
  }

[ which is more efficient using the standard GP parser ]

Cheers,

    Karim.
-- 
Karim Belabas                     Tel: (+33) (0)1 69 15 57 48
Dep. de Mathematiques, Bat. 425   Fax: (+33) (0)1 69 15 60 19
Universite Paris-Sud              http://www.math.u-psud.fr/~belabas/
F-91405 Orsay (France)            http://pari.math.u-bordeaux.fr/  [PARI/GP]