#8327: Implement the universal cyclotomic field, using Zumbroich basis
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Reporter: nthiery | Owner:
Type: enhancement | Status:
needs_review
Priority: major | Milestone: sage-5.6
Component: number fields | Resolution:
Keywords: Cyclotomic field, Zumbroich basis | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Christian Stump, Simon King | Merged in:
Dependencies: #13727, #13728 | Stopgaps:
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Comment (by nthiery):
Replying to [comment:122 stumpc5]:
> > * why is the hash function test tagged with random ? does it depend on
the computer or something like that ?
>
> If I am not mistaken, the hash is only unique in a given Sage session.
It is not required that the hash value of an object be unique across
Sage session. However the implementation usually guarantees this,
which is a good feature. In fact, most of the time in Sage, the hash
value only depends on the architecture (32bits/64bits) and when this
is the case, it is good to test it explicitly in order to get noticed
in case the hash value would change for some reason (which could be a
bug or a long distance consequence of something else), as in:
sage: e = RootSystem(['A',2]).ambient_space()
sage: hash(e.simple_root(0))
-4601450286177489034 # 64-bit
549810038 # 32-bit
Cheers,
Nicolas
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8327#comment:123>
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