Improvements to units convert function

[eviatarbach]

Previously, there were some problems with the unit convert function, namely that variables were not allowed. The following now works:

sage: sage.symbolic.units.convert(50 * x * units.area.square_meter, units.area.acre)
(1953125/158080329*x)*acre

As well, previously units were sometimes "mixed" with the returned symbolic (see http://ask.sagemath.org/question/641/radian-degree-conversion). Now, the following works:

sage: sage.symbolic.units.convert(cos(50) * units.angles.radian, units.angles.degree)
(180*cos(50)/pi)*degree

CC: @eviatarbach

Component: symbolics

Keywords: units

Author: Eviatar Bach

Reviewer: Burcin Erocal

Merged: sage-4.7.2.alpha1

Issue created by migration from https://trac.sagemath.org/ticket/11592

[burcin]

Author: Eviatar Bach

[burcin]

comment:5

Thanks for the patch. Looks good to me, though a few minor changes are necessary before I can switch to positive review.

The patch bot shows failing tests in sage/symbolic/expression.pyx. While fixing those, please update the commit message to contain something meaningful in the first line. Deleting the first 2 lines of the current message should suffice.

[burcin]

Reviewer: Burcin Erocal

[burcin]

Changed keywords from none to units

[eviatarbach]

comment:6

Attachment: 11592.patch.gz

Great! New patch uploaded.

[eviatarbach]

comment:7

It there something wrong with the patchbot? My local copy is passing all the tests.

[jdemeyer]

Merged: sage-4.7.2.alpha1