From: SourceForge.net <noreply@so...>  20070823 02:20:18

Bugs item #696804, was opened at 20030303 11:52 Message generated for change (Comment added) made by sfrobot You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=696804&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core  Polynomials Group: None >Status: Closed Resolution: Fixed Priority: 5 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: factor FAILS on polynomial !!! Initial Comment: Factor fails to factor a polynomial in two variables. p: (23*x^10*y^5 + 82*x^9*y^4 + 80*x^8*y^4  28*x^7*y^3  47*x^6*y^3  74*x^5*y^2 + 28*x^4*y^2  74*x^3*y + 25*x^2*y + 21*x  41) * (78*x^10*y^5 + 49*x^9*y^4 + 48*x^8*y^4 + 49*x^7*y^3 + 65*x^6*y^3  8*x^5*y^2 + 82*x^4*y^2  7*x^3*y  15*x^2*y  6*x + 30) factor(expand(p)) => irreducible If this is some intentional limitation, it should give some sort of warning. But I don't see why it should be. This was a polynomial generated randomly using: product(sum((random(200)100) * x^i * y^entier(i/2), i,0,10), j,1,2) Sometimes these polynomials factor correctly, but mostly they come back as irreducible. I tried setting Berlefact:false to see if that would make a difference, but that causes an internal error (POWERSET requires less than two arguments). I also tried using rat instead of expand to make sure it wasn't a multiplication problem rather than a factoring problem. Maxima version: 5.9.0 Maxima build date: 19:10 2/9/2003 host type: i686pcmingw32 lispimplementationtype: Kyoto Common Lisp lispimplementationversion: GCL25.0  >Comment By: SourceForge Robot (sfrobot) Date: 20070822 19:20 Message: Logged In: YES user_id=1312539 Originator: NO This Tracker item was closed automatically by the system. It was previously set to a Pending status, and the original submitter did not respond within 14 days (the time period specified by the administrator of this Tracker).  Comment By: Dan Gildea (dgildea) Date: 20070808 05:59 Message: Logged In: YES user_id=1797506 Originator: NO fixed in cvs. incrlimk was not setting integer modulus big enough  removed buggy logtwo and logn routines.  Comment By: Robert Dodier (robert_dodier) Date: 20060909 07:14 Message: Logged In: YES user_id=501686 All three examples behave the same in Maxima 5.9.3cvs.  Comment By: Stavros Macrakis (macrakis) Date: 20030917 16:19 Message: Logged In: YES user_id=588346 Here is the smallest (degree and maximum product coefficient) case I've been able to find: (35*x*y^2+19*x^2+25) * (35*x*y^2+25*x^2+19) Found by a combination of randomized and systematic searching. The larger the coefficients, the denser the failure cases. Maxima 5.9.0 gcl 2.5.0 mingw32 W2k Athlon  Comment By: Stavros Macrakis (macrakis) Date: 20030916 06:28 Message: Logged In: YES user_id=588346 Another factor failure: (34*y^3+987*x*y23*x^31)*(234*x^23*y^45 978*x^43*y^10+1) Setting berlefact:false gives error: POWERSET [or a callee] requires less than two arguments.  Comment By: Barton Willis (willisb) Date: 20030304 13:16 Message: Logged In: YES user_id=570592 Macsyma 2.2 also fails to factor p after it has been expanded. Setting berlefact : false didn't make any difference. Barton  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=696804&group_id=4933 