#12967: bugs in comparisons between constants, wrapped pyobjects, infinity
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Reporter: dkrenn | Owner: burcin
Type: defect | Status: needs_work
Priority: major | Milestone: sage-6.6
Component: symbolics | Resolution:
Keywords: compare pi | Merged in:
infinity bool | Reviewers: Karl-Dieter Crisman
Authors: Travis Scrimshaw, | Work issues:
Ralf Stephan | Commit:
Report Upstream: N/A | c5845f6b18d582807dafaaf60ad6a5c8017173f3
Branch: u/rws/12967-2 | Stopgaps:
Dependencies: #17984 |
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Comment (by pbruin):
Replying to [comment:37 mmezzarobba]:
> Replying to [comment:35 pbruin]:
> > `bool(pi == 3.14[...])` returns `True` if the approximation is correct
to the given precision?
>
> This sounds very dangerous to me.
In fact, `bool(pi == pi.n())` already returns `True`, which I think is
reasonable. In any case it is consistent with how elements of real fields
of different precisions are compared.
The question is whether we also want to use this for `x in RR`. I
currently cannot think of a natural way of implementing this. Just
checking whether `x` can be converted in to `RR` is not enough (as the
example with `Mod(1, 2)` in comment:35 shows); one would at least expect
that `x` can be converted into `RR` ''and'' that the result is
"sufficiently equal" to the original `x`.
--
Ticket URL: <http://trac.sagemath.org/ticket/12967#comment:41>
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