#14411: Disjoint Sets --> iter
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Reporter: elixyre | Owner: jason, ncohen, rlm
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.10
Component: misc | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers: Travis Scrimshaw
Authors: Jean-Baptiste Priez | Merged in:
Dependencies: | Stopgaps:
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Comment (by tscrim):
You're forgetting that this is not a dijoint union as a ''mathematical''
object but a specific ''data structure'' of `DisjointSet` which is not a
list of lists. In some sense, there is less structure as `DisjointSet` is
better described as a map from elements to a representative (in particular
the subsets are not ordered). Thus the most logical behavior to me is that
`__getitem__()` should match `find()`.
Actually considering that, the iterator should the representatives (i.e.
the `iterkeys()`) and not the subsets.
To reiterate, this is a tool (class) used to solve problems efficiently,
not to represent a mathematical structure. The mathematical structure
you're after would either be `DisjointUnionEnumeratedSets` or
`SetPartitions`. If you really want to return the whole subset from an
element, this should get its own specialized method.
Best,[[BR]]
Travis
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14411#comment:9>
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