[Maxima-bugs] [ maxima-Bugs-836708 ] rat/tellrat/modulus:2 can return -1

[SourceForge.net <no...@so...>]

Bugs item #836708, was opened at 2003-11-05 20:00
Message generated for change (Comment added) made by wjenkner
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=836708&group_id=4933

Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Stavros Macrakis (macrakis)
Assigned to: Nobody/Anonymous (nobody)
Summary: rat/tellrat/modulus:2 can return -1

Initial Comment:
algebraic:true$ modulus:2$
tellrat(a^2+a)$

rat(a^2) => - a

With modulus=2, -1 is supposed to simplify to 1.

This can be fixed (bizarrely) by ev:

    ev(%) => a




----------------------------------------------------------------------

>Comment By: Wolfgang Jenkner (wjenkner)
Date: 2003-11-07 18:38

Message:
Logged In: YES 
user_id=581700

On both SBCL and CLISP I get the expected result

(C4) rat(a^2);
(D4)/R/                                a

I'd guess this is the same GCL specific misfeature as #706562
(mod(-2,4) => -2 not 2).


----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=104933&aid=836708&group_id=4933