#15650: Permutations and symmetric group algebra: getting rid of 'mult' global
in
seminormal form
-------------------------------------+-------------------------------------
Reporter: darij | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.1
Component: combinatorics | Keywords: permutation,
Merged in: | sage-combinat, descent algebra,
Reviewers: | symmetric group, seminormal form
Work issues: | Authors: Darij Grinberg
Commit: | Report Upstream: N/A
e8b22ee5eaaf6cd0a7390b4c6167e7fa9998bd60| Branch:
Stopgaps: | public/combinat/seminormal
| Dependencies:
-------------------------------------+-------------------------------------
This is a sequel to #15174. The purpose of this ticket is to get rid of
all uses of the `PermutationOptions['mult']` global variable which
determines how the product of two permutations is defined. Getting rid of
the variable itself (#14885) will be tougher.
Specifically, my branch does the following:
- All methods related to the seminormal form in
`sage/combinat/symmetric_group_algebra.py` now no longer rely on
`PermutationOptions['mult']`. Instead, the ones among them that used to
have their result depend on `'mult'` now take an optional keyword `'mult'`
(defaulting to `l2r`, not to the global setting -- not sure if this is
good?).
- The exposed seminormal-form methods now are documented. The
documentation might look weird and might also be wrong at times, since my
acquaintance with the seminormal form is half a day old (sorry, Andrew,
for procrastinating on this!!) and since the methods were obviously
written with British multiplication in mind (`pq` = first `p` then `q`)
whereas I'm using continental multiplication (`pq` = first `q` then `p`).
I hope someone experienced can review this, because I'm not actually sure
I made anything better...
- Descent algebra documentation has been corrected at a few points. The
errors were my own and were due to me not knowing that Sage uses British
multiplication. (Ceterum censeo, the continental convention is still the
right one.)
- A few minor speedups and doc improvements on the permutation code.
--
Ticket URL: <http://trac.sagemath.org/ticket/15650>
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/groups/opt_out.
