Update documentation for EnumeratedFamily

[trevorkarn]

The current documentation implies that the index set must be finite. This is not the case:

sage: F = Family(ZZ)
sage: type(F)
<class 'sage.sets.family.EnumeratedFamily_with_category'>

CC: @tscrim

Component: documentation

Keywords: gsoc2022 documentation family

Author: Trevor K. Karn

Branch/Commit: c777eca

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/34054

[tscrim]

comment:2

I am not sure the documentation is wrong, but it might be a slight abuse of notation. In particular |ZZ| is aleph₀, and aleph₀ - 1 = aleph₀ (well, this might make slightly more sense in terms of ordinals rather than cardinals). So it is saying it is indexed by {0, 1, ...}.

Now your change definitely is wrong because it is not indexed by Z but by N (with 0) in the infinite case. Don't let this run for too long:

sage: F = Family(ZZ)
sage: F[-1]

as the generic unrank() from the category doesn't protect against bad input (for infinite enuemrated sets, IMO, it should).

[sagetrac-git]

Changed commit from d4dedf6 to 79250c6

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

79250c6

Add documentation of Integer index

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

f11c1a3

Add check for positivity of rank

[sagetrac-git]

Changed commit from 79250c6 to f11c1a3

[trevorkarn]

comment:5

I changed this to reflect your comment about ZZ[-1], and then saw that _unrank_from_iterator expects a positive rank, but does not check for it, so I added the check there.

[tscrim]

comment:7

There is no reason for a separate TESTS:: block. I would also put the ZZ test below the C one to have better grouping of the tests.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

250ee34

Remove TESTS block

[sagetrac-git]

Changed commit from f11c1a3 to 250ee34

[mkoeppe]

comment:9

+            if r < 0:
+                raise ValueError("the value must be greater than or equal to 0")

I'd suggest to change from "value" to "rank" here.

Otherwise LGTM

[mkoeppe]

comment:10

Maybe it would also be a good idea to check that it's an integer?

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

19f5820

value->rank and check for integer value

[sagetrac-git]

Changed commit from 250ee34 to 19f5820

[mkoeppe]

comment:12

I would rephrase "must be between %s and %s inclusive" -> "must be in the range from %s to %s"

[mkoeppe]

comment:13

I know that this is not from your ticket, but this:

             counter = 0
             for u in self:
                 if counter == r:
                     return u
                 counter += 1

could be rewritten using enumerate

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

cd816e6

Rephrase range

[sagetrac-git]

Changed commit from 19f5820 to cd816e6

[sagetrac-git]

Changed commit from cd816e6 to c777eca

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

c777eca

Rewrite using enumerate and fix doctests

[mkoeppe]

Reviewer: Matthias Koeppe

[vbraun]

Changed branch from u/tkarn/enumerated-family-ZZ-doc to c777eca