#19555: Implement a containment for cartesian_product
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Reporter: tscrim | Owner: sage-combinat
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.10
Component: combinatorics | Resolution:
Keywords: | Merged in:
Authors: Travis Scrimshaw | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
public/sets/contains_cartesian_product-19555|
f1d029a3a3518265f1f88c2438bbc9b00c7ecd36
Dependencies: | Stopgaps:
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Comment (by vdelecroix):
I fully agree on the above example and there are many others. As you said,
wrapping has a cost. Having an option looks reasonable
{{{
sage: C = cartesian_product([range(5), range(5)],
with_elements_as_tuple=True)
sage: C.element_class
<type 'tuple'>
}}}
Though, I am just asking for your opinion. I am not considering it good
for inclusion in this ticket.
On the other hand, with your laxism with respect to tuples the equality
test is about 3x slower. We had
{{{
sage: C = cartesian_product([srange(5), srange(5)])
sage: c = C((1,1))
sage: d = C((1,1))
sage: e = C((1,2))
sage: %timeit c == d and c == e
1000000 loops, best of 3: 327 ns per loop
}}}
And with your branch
{{{
sage: %timeit c == d and c == e
100000 loops, best of 3: 1.93 µs per loop
}}}
If the comparison has to be touched, it has to be at the level of
`ElementWrapper`. Probably a new class.
--
Ticket URL: <http://trac.sagemath.org/ticket/19555#comment:17>
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