Thank you for this reference I will look at it. But the main problem is not there. I have my existing software for polyhedral computations of polytope defined over the rational numbers. I want to work with 600-cell, 120-cell whose vertices are defined over Q(Sqrt(5)) preferably without having to modify the code.
The question is on the structure of GAP itself. Is it possible to redefine the ">" test so that it is the natural order of the real field, which is used, when comparing two elements of Q(Sqrt(5)) ? Mathieu On Tue, Aug 07, 2007 at 12:19:20PM +0300, [EMAIL PROTECTED] wrote: >> One can implement in GAP exact algorithms for real algebraic numbers, as >> described e.g. in the recent monograph Algorithms in Real Algebraic Geometry >> by Basu, Pollack, and Roy (there is also an online version of it on the >> net). >> But this is quite a bit of work. >> HTH, >> Dima >> >> -original message- >> Subject: [GAP Forum] Real field >> From: "Mathieu Dutour" <[EMAIL PROTECTED]> >> Date: 06/08/2007 13:37 >> >> Dear all, >> >> I would like to work with numbers of the form (1+Sqrt(5))/2 >> in order to work with 600-cell, 120-cell and such kind of >> polytopes. >> >> Currently such numbers are coded in GAP with cyclotomic >> extensions, which means that we have no comparison and functions >> like (1+Sqrt(5))/2 > 30 does not return what I would like. >> >> Is there a way to code a real field like Q(Sqrt(5)) in GAP >> so as to have reliable comparison operator? >> >> -- >> Mathieu Dutour Sikiric Researcher in Mathematics >> Telephone:.(+385)1 4571 237 and Computer Science >> Cell Phone: (+385)9 19 36 30 80 Laboratory of satellite oceanography >> E-mail: [EMAIL PROTECTED] Rudjer Boskovic Institute >> http://www.liga.ens.fr/~dutour Zagreb Croatia >> skype name: mathieudutour >> >> _______________________________________________ >> Forum mailing list >> [email protected] >> http://mail.gap-system.org/mailman/listinfo/forum -- Mathieu Dutour Sikiric Researcher in Mathematics Telephone:.(+385)1 4571 237 and Computer Science Cell Phone: (+385)9 19 36 30 80 Laboratory of satellite oceanography E-mail: [EMAIL PROTECTED] Rudjer Boskovic Institute http://www.liga.ens.fr/~dutour Zagreb Croatia skype name: mathieudutour _______________________________________________ Forum mailing list [email protected] http://mail.gap-system.org/mailman/listinfo/forum
