PARI/GP Bug report logs - #1151
rnfequation(,,1) is broken

Package: pari; Maintainer for pari is Aurel Page <aurel.page@normalesup.org>; Source for pari is src:pari.

Reported by: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>

Date: Sat, 18 Dec 2010 16:03:01 UTC

Severity: normal

Done: Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>

Bug is archived. No further changes may be made.

Full log

🔗 View this message in rfc822 format

X-Loop: allomber@math.u-bordeaux.fr
Subject: Bug#1151: rnfequation(,,1) is broken
Reply-To: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>, 1151@pari.math.u-bordeaux.fr
Resent-From: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>
Resent-To: bug-submit-list@pari.math.u-bordeaux.fr
Resent-CC: Karim.Belabas@math.u-bordeaux.fr
Resent-Date: Tue, 01 Feb 2011 16:33:02 UTC
Resent-Message-ID: <handler.1151.B1151.129657731824124@pari.math.u-bordeaux.fr>
Resent-Sender: allomber@math.u-bordeaux.fr
X-PARI/GP-PR-Message: report 1151
X-PARI/GP-PR-Package: pari
X-PARI/GP-PR-Keywords: 
Received: via spool by 1151-submit@pari.math.u-bordeaux.fr id=B1151.129657731824124
          (code B ref 1151); Tue, 01 Feb 2011 16:33:02 UTC
Received: (at 1151) by pari.math.u-bordeaux.fr; 1 Feb 2011 16:21:58 +0000
Received: from smail.math.u-bordeaux1.fr ([147.210.16.22])
	by pari.math.u-bordeaux1.fr with esmtp (Exim 4.69)
	(envelope-from <Bill.Allombert@math.u-bordeaux1.fr>)
	id 1PkIzO-0006H3-8y
	for 1151@pari.math.u-bordeaux.fr; Tue, 01 Feb 2011 17:21:58 +0100
Received: from localhost (localhost [127.0.0.1])
	by smail.math.u-bordeaux1.fr (Postfix) with ESMTP id 4EDF951942
	for <1151@pari.math.u-bordeaux.fr>; Tue,  1 Feb 2011 17:21:53 +0100 (CET)
X-Virus-Scanned: amavisd-new at math.u-bordeaux1.fr
Received: from smail.math.u-bordeaux1.fr ([127.0.0.1])
	by localhost (smail.math.u-bordeaux1.fr [127.0.0.1]) (amavisd-new, port 10025)
	with LMTP id SvmmGZtALGau for <1151@pari.math.u-bordeaux.fr>;
	Tue,  1 Feb 2011 17:21:49 +0100 (CET)
Received: from yellowpig (unknown [147.210.21.245])
	by smail.math.u-bordeaux1.fr (Postfix) with ESMTP id 5BD6E511B6
	for <1151@pari.math.u-bordeaux.fr>; Tue,  1 Feb 2011 17:21:49 +0100 (CET)
Received: from bill by yellowpig with local (Exim 4.72)
	(envelope-from <Bill.Allombert@math.u-bordeaux1.fr>)
	id 1PkIzF-00064t-Ll
	for 1151@pari.math.u-bordeaux.fr; Tue, 01 Feb 2011 17:21:49 +0100
Date: Tue, 1 Feb 2011 17:21:49 +0100
From: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>
To: 1151@pari.math.u-bordeaux.fr
Message-ID: <20110201162149.GF3266@yellowpig>
References: <20101218155503.GC9570@yellowpig>
 <20110131235925.GE3266@yellowpig>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="i0/AhcQY5QxfSsSZ"
Content-Disposition: inline
In-Reply-To: <20110131235925.GE3266@yellowpig>
User-Agent: Mutt/1.5.20 (2009-06-14)

[Message part 1 (text/plain, inline)]
On Tue, Feb 01, 2011 at 12:59:25AM +0100, Bill Allombert wrote:
> On Sat, Dec 18, 2010 at 04:55:03PM +0100, Bill Allombert wrote:
> > Package: pari
> > Version: 2.4.3, 2.3.5
> > 
> > Hello Karim,
> > This issue was reported on the pari-users list
> > <http://pari.math.u-bordeaux.fr/archives/pari-users-1012/msg00004.html>.
> > I report it for reference.
> > 
> > ? f = (y^17-1)/(y-1);
> > ? g = Mod(1,f)*x+Mod(y^6,f);
> > ? rnfequation(f,g,1);
> >   ***   at top-level: rnfequation(f,g,1)
> >   ***                 ^------------------
> >   *** rnfequation: the PARI stack overflows !
> 
> Well, according to my calculation the correct LERS is:
> (-x^4 + x^3 - x^2)*y + (-x^7 + x^6 - x^5)
> 
> Furthermore, the values returned by Flx_resultant_all for x=2 are 144 times too large.
> For x=3 the values are random but the quotient H0/H1 seems correct

The attached patch is probably incorrect, but it allows both 'make test-all' and 
this test
for(i=1,16,print(i);rnfequation(polcyclo(17,y),-x+y^i,1))

to work. Strange...

Bill.

[patch (text/plain, attachment)]

Send a report that this bug log contains spam.

Bill Allombert <allomber@math.u-bordeaux.fr>. Last modified: Sat Aug 26 17:27:13 2023; Machine Name: pari

PARI/GP Bug tracking system

Debbugs is free software and licensed under the terms of the GNU Public License version 2. The current version can be obtained from https://bugs.debian.org/debbugs-source/.

Copyright © 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson, 2005-2017 Don Armstrong, and many other contributors.