#13687: Parents for groups
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Reporter: vbraun | Owner: joyner
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.5
Component: group theory | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Description changed by vbraun:
Old description:
> Groups are based on the deprecated `ParentWithGens`. This ticket is about
> forward-porting them to the new coercion framework.
>
> To limit the size of the patchbomb I'm only porting the Abelian groups.
> The rest depends on `old.Group`
>
> Various oddities needed to be cleaned up in the process:
> * make parents unique and elements immutable (often requires tuples
> instead of lists)
> * rename `AbelianGroup_class.invariants()` ->
> `AbelianGroup_class.gens_orders()` since they are not necessarily the
> abelian invariants (=elementary divisors).
> * rename `element.list()` -> `element.exponents()` for the exponent
> vector.
> * implement a `AbelianGroupWithValues` where you attach values to the
> (abstract) generators. Used in the unit group of a number field, for
> example.
> * lots of places return lists when they should return tuples
New description:
Groups are based on the deprecated `ParentWithGens`. This ticket is about
forward-porting them to the new coercion framework.
To limit the size of the patchbomb I'm only porting the Abelian groups.
The rest depends on `old.Group`
Various oddities needed to be cleaned up in the process:
* make parents unique and elements immutable (often requires tuples
instead of lists)
* rename `AbelianGroup_class.invariants()` ->
`AbelianGroup_class.gens_orders()` since they are not necessarily the
abelian invariants (=elementary divisors).
* rename `element.list()` -> `element.exponents()` for the exponent
vector.
* implement a `AbelianGroupWithValues` where you attach values to the
(abstract) generators. Used in the unit group of a number field, for
example.
* lots of places return lists when they should return tuples
I haven't actually deprecated `.invariants()` and `.list()`, just changed
the documentation to suggest the equivalent `.gens_orders()` and
.exponents()` methods. But I think we should deprecate them. Though I
first want to work my way through the remaining groups code.
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13687#comment:3>
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