#15786: floor fails for certain expressions.
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Reporter: fwclarke | Owner:
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.8
Component: symbolics | Resolution:
Keywords: floor | Merged in:
Authors: David Einstein | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/deinst/15786-floor | 16e522fb6876ce646af7c52348056b94f3b8dfbc
Dependencies: | Stopgaps:
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Comment (by rws):
Just to complete the picture:
Replying to [comment:12 deinst]:
>... Although the `Expression` object has an `is_integer` method, it does
not seem to have any way of getting that integer other than calling
`floor` or `ceil`.
This calls Pynac and performs a call to `ex::info(info_flags)` which is
virtual so you have methods named `info()` for all subclasses of `basic`,
see http://www.ginac.de/tutorial/#The-class-hierarchy. In fact, only
`add`, `mul`, and `numeric` have any handling of that flag, the relevant
code is here:
* https://github.com/pynac/pynac/blob/master/ginac/add.cpp#L263
* https://github.com/pynac/pynac/blob/master/ginac/mul.cpp#L469
* https://github.com/pynac/pynac/blob/master/ginac/numeric.cpp#L1101
The last calls back Sage's function `symbolic/pynac.pyx:cdef public bint
py_is_integer()` which is
{{{
return isinstance(x, int) or isinstance(x, long) or isinstance(x,
Integer) or \
(isinstance(x, Element) and
((<Element>x)._parent.is_exact() or (<Element>x)._parent ==
ring.SR) and
(x in ZZ))
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/15786#comment:13>
Sage <http://www.sagemath.org>
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