Karim BELABAS on Sat, 15 Mar 2003 15:29:46 +0100 (MET) |
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Re: QX_caract |
On Wed, 5 Mar 2003, Bill Allombert wrote: > Why not use the modular algorithm of ZX_caract directly in QX_caract > instead of removing the content and calling ZX_caract ? [...] > Of course I have not addressed how to implement this, in particular > how to know we have a sufficiently large modulus. For this to work, the result needs to be in Z[X], wich is not the current specification of QX_caract. Hum. Well, there's no documented specification, and the current behaviour is already incoherent (one argument is assumed to be integral). So I might as well assume the result is integral, since it's the only situation which is of interest here. ... OK, this is implemented in CVS. The modulus bound is rigorous (~ Hadamard bound + floating point computation if bound is huge). I have removed QX_caract: simply some of the ZX_* functions tolerate a non-integral argument _provided_ the result is integral. As they already did in fact [ replacing the QX_caract call by ZX_caract would have worked ! ] I know, all of this needs to be documented ... Cheers, Karim. -- Karim Belabas Tel: (+33) (0)1 69 15 57 48 Dép. de Mathématiques, Bât. 425 Fax: (+33) (0)1 69 15 60 19 Université Paris-Sud http://www.math.u-psud.fr/~belabas/ F-91405 Orsay (France) http://www.parigp-home.de/ [PARI/GP]