Opened 2 years ago
Last modified 3 months ago
#28602 new enhancement
allow user to specify order of the hyperplanes in a hyperplane arrangement
Reported by: | saliola | Owned by: | |
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Priority: | major | Milestone: | sage-9.5 |
Component: | geometry | Keywords: | hyperplane arrangement |
Cc: | tscrim, galen-dorp, nailuj | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
The objective of this ticket is to allow the user to specify the order of the hyperplanes when constructing a hyperplane arrangement. There are various reasons why a user might want to use a custom ordering, for example, to specify the order of the components in the sign vector, to specify the labelling of the elements of the associated matroid, etc.
Currently, the order of the hyperplanes is ignored as Sage just sorts the list of hyperplanes:
sage: H.<x,y> = HyperplaneArrangements(QQ) sage: H(x, y, x-1, y-1) Arrangement <y - 1 | y | x - 1 | x>
For backwards compatibility, we could implement a keyword argument, say sort=False
that defaults to sort=True
to preserve the current behaviour:
sage: H.<x,y> = HyperplaneArrangements(QQ) sage: H(x, y, x-1, y-1, sort=True) # default Arrangement <y - 1 | y | x - 1 | x> sage: H(x, y, x-1, y-1, sort=False) # desired behaviour Arrangement <x | y | x - 1 | y - 1>
Change History (7)
comment:1 Changed 2 years ago by
- Cc nailuj added
comment:2 Changed 2 years ago by
comment:3 Changed 22 months ago by
- Milestone changed from sage-9.0 to sage-9.1
Ticket retargeted after milestone closed
comment:4 Changed 19 months ago by
- Milestone changed from sage-9.1 to sage-9.2
Batch modifying tickets that will likely not be ready for 9.1, based on a review of the ticket title, branch/review status, and last modification date.
comment:5 Changed 14 months ago by
- Milestone changed from sage-9.2 to sage-9.3
comment:6 Changed 9 months ago by
- Milestone changed from sage-9.3 to sage-9.4
Setting new milestone based on a cursory review of ticket status, priority, and last modification date.
comment:7 Changed 3 months ago by
- Milestone changed from sage-9.4 to sage-9.5
I like this idea a lot. I propose to add the same keyword argument to the
union
method of aHyperplaneArrangement
to preserve the order when adding a hyperplane or an arrangement to the current ordered one.