#19609: Added image and kernel methods to morphisms of finite-dimensional
modules
with basis
-------------------------------------+-------------------------------------
Reporter: tscrim | Owner: sage-combinat
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.10
Component: linear algebra | Resolution:
Keywords: kernel, image, | Merged in:
module morphism | Reviewers:
Authors: Travis Scrimshaw | Work issues:
Report Upstream: N/A | Commit:
Branch: | 289d8c22e5fca2ef89131e7095516861bdd8e3d1
public/categories/image_kernel_module_morphism-19609| Stopgaps:
Dependencies: |
-------------------------------------+-------------------------------------
Comment (by tscrim):
Replying to [comment:2 virmaux]:
> It is definitely very usefull!
> Just a few (maybe useless) remarks. The basis method usually returns a
Family (Finite, Lazy or ...), may we want to do the same for the kernel
instead of a tuple?
All of the other `*_basis` (like `radical_basis`) returned lists. I
changed these to tuples because the output is cached (so should be
immutable) and for consistency.
There was also an issue that I could not use cached methods on the
morphisms because the equality test used `__dict__`. However, I decided to
not make the results cached because if the basis order changed, then one
can get different bases for the kernel/image, which may be desirable.
> Also, we may want to document the choice of right kernel versus left
kernel.
I think there is only the right kernel because I chose to use the right
matrix version and there is no ambiguity. Perhaps I'm not thinking of
something...
--
Ticket URL: <http://trac.sagemath.org/ticket/19609#comment:5>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
