#6699: [with new spkg and patch; needs review] Update to Maxima 5.19.1
(particularly important for Solaris support).
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Reporter: drkirkby | Owner: mabshoff
Type: defect | Status: new
Priority: major | Milestone: sage-4.1.2
Component: packages | Keywords: maxima
Reviewer: | Author: David Kirkby, Alex Ghitza
Merged: |
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Comment(by AlexGhitza):
Here's a description of the problem and the workaround patched in the
latest spkg:
We are calling Maxima's function {{{to_poly_solve}}} on the symbolic
expression {{{Q*sqrt(Q^2+2)-1 == 0}}}. Maxima takes this expression and
turns it into a system of polynomial equations, and possibly some
inequalities giving constraints on the variables. This is done by a
function in {{{share/contrib/topoly.lisp}}}. This function behaves
differently under Maxima 5.19.1 than it did under Maxima 5.16.3, and
that's what is causing Maxima to lose one of the solutions:
Maxima 5.16.3:
{{{
sage: var('Q');
sage: ex = Q*sqrt(Q^2+2)-1 == 0
sage: m = ex._maxima_()
sage: m.to_poly()
[[%g0*Q-1,Q^2+2=%g0^2],[-%pi/2<carg(%g0),carg(%g0)<=%pi/2]]
}}}
Maxima 5.19.1:
{{{
sage: var('Q');
sage: ex = Q*sqrt(Q^2+2)-1 == 0
sage: m = ex._maxima_()
sage: m.to_poly()
[[%g0*Q-1,Q^2+2=%g0^2],[-%pi/2<parg(%g0),parg(%g0)<=%pi/2],[]]
}}}
The main difference between the two is that {{{carg}}} turned into
{{{parg}}}. The latter is a new function which is supposed to be a
lightweight alternative to {{{carg}}}.
The right way to fix this is to properly debug {{{topoly.lisp}}} and send
a patch to Maxima, but I do not have the time or expertise to do that.
The author knows about the bug (see above link to maxima mailing list), so
hopefully this will get sorted out in a future release of Maxima.
For now, I'm patching {{{topoly.lisp}}} so that the appropriate
occurrences of {{{parg}}} are changed back into {{{carg}}}. This solves
our doctest failure.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/6699#comment:11>
Sage <http://sagemath.org/>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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