#11556: Linear transformations, built from free module morphisms
------------------------------+---------------------------------------------
Reporter: rbeezer | Owner: jason, was
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.7.2
Component: linear algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: Martin Raum | Author: Rob Beezer
Merged: | Dependencies: #11552, #11553
------------------------------+---------------------------------------------
Old description:
> This patch builds vector space morphisms, aka linear transformations,
> from free module morphisms. This allows for a few specialized methods,
> such as an easier test for invertibility (check the rank of a matrix
> representation). But it is mostly about (a) a "linear transformation"
> constructor for beginners' use, (b) lots of documentation, (c)
> specialized output routines, so it is clear when a morphism runs between
> two vecto5r space (not just two free modules).
>
> (c) required lots of doctest changes. When the example was complicated
> and involved two vector spaces, I usually changed the output to match the
> new format for the new morphisms. When teh example was simple, I tried
> to "roll it back" to involve two free modules, to fully exercise that
> code.
>
> Additionally, there were a lot of doctests with matrices of the wrong
> size, reversing domain and codomain, that managed to pass due to the bug
> listed in #10793. Tighter controls here required fixing a lot of these.
>
> '''Depends:'''
> 1. #11552
> 1. #11553
>
> '''Apply:'''
> 1. [attachment:trac_11556-linear-transformations-v4.patch]
New description:
This patch builds vector space morphisms, aka linear transformations, from
free module morphisms. This allows for a few specialized methods, such as
an easier test for invertibility (check the rank of a matrix
representation). But it is mostly about (a) a "linear transformation"
constructor for beginners' use, (b) lots of documentation, (c) specialized
output routines, so it is clear when a morphism runs between two vecto5r
space (not just two free modules).
(c) required lots of doctest changes. When the example was complicated
and involved two vector spaces, I usually changed the output to match the
new format for the new morphisms. When teh example was simple, I tried to
"roll it back" to involve two free modules, to fully exercise that code.
Additionally, there were a lot of doctests with matrices of the wrong
size, reversing domain and codomain, that managed to pass due to the bug
listed in #10793. Tighter controls here required fixing a lot of these.
'''Depends:'''
1. #11552
1. #11553
'''Apply:'''
1. [attachment:trac_11556-linear-transformations-v4.patch]
1. [attachment:trac_11556-linear-transformations-edits.patch]
--
Comment(by rbeezer):
"edits" patch addresses all of the reviewer suggestions, except linearity
testing. I'm open to trying new things to improve error-checking for
linear function input.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11556#comment:9>
Sage <http://www.sagemath.org>
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