Dirk Laurie on Sun, 24 Jun 2012 07:58:59 +0200


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Fwd: Missing bnf functions


---------- Forwarded message ----------
From: Dirk Laurie <dirk.laurie@gmail.com>
Date: 2012/6/24
Subject: Re: Missing bnf functions
To: Malcolm Bovey <malcolm.bovey@gmail.com>


2012/6/24 Malcolm Bovey <malcolm.bovey@gmail.com>:
>
> I'm having trouble running some code on a Mac OS X (v 10.6.8) installation. Â I downloaded and compiled the latest stable version of PARI-GP (2.5.1) - this seemed to be successful. ÂHowever, PARI doesn't seem to know about some internal functions that it should do. ÂFor example, when I try using bnfclassunit, I get
>
> bnfclassunit(x^2-5)
> Â*** Â at top-level: bnfclassunit(x^2-5)
> Â*** Â Â Â Â Â Â Â Â ^-------------------
> Â*** Â not a function in function call
> Â*** Â Break loop: type 'break' to go back to GP
>
> bnfinit seems to work fine.
>
> Any suggestions as to what's going wrong here?
>

This is the list of function names starting "bnf" according to "?6":

bnfcertify     bnfcompress    Âbnfdecodemodule  Âbnfinit
bnfisintnorm    bnfisnorm     Âbnfisprincipal   bnfissunit
bnfisunit     Âbnfnarrow     Âbnfsignunit    Âbnfsunit

Moreover, the word `bnfclassunit` does not appear anywhere in the TeX
source of any of the manuals. ÂSo Pari seems not to be at fault.

Are you by any chance confusing functions with member functions?
These are functions of one variable that you call with x.foo instead
of foo(x), and they have their own namespace. ÂYou can define you own,
for example:

? z.re=real(z)
%13 = (z)->real(z)

Some member functions are built-in. ÂSee "?.". ÂThere's no "classunit",
but there is "fu":

 ÂB=bnfinit(x^2-x-1);
 ÂB.fu
%2 = [Mod(1/2*x + 1/2, x^2 - 5)]

HTH

Dirk