#15360: Implement custom max()
-----------------------------+------------------------------
Reporter: tmonteil | Owner: tmonteil
Type: defect | Status: needs_info
Priority: major | Milestone: sage-7.1
Component: numerical | Resolution:
Keywords: RIF | Merged in:
Authors: | Reviewers: Jeroen Demeyer
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Changes (by jdemeyer):
* milestone: sage-duplicate/invalid/wontfix => sage-7.1
Old description:
> `Real interval field` relies on MPFI, which is reliable. But Sage uses it
> in a wrong way in various places in the code, making the use of `Real
> interval field` not reliable, hence providing a wrong feeling of
> security. Here are two examples:
>
> {{{
> sage: max(RIF(2,3), RIF(1,4)).endpoints()
> (2.00000000000000, 3.00000000000000)
> }}}
>
> {{{
> sage: x = -(25510582*pi - 80143857)/(52746197*pi - 165707065)
> sage: int(x)
> ValueError: Calling floor() on infinity or NaN
> }}}
>
> (this example is related to this ask question :
> http://ask.sagemath.org/question/3179/continued-fraction-of-pi-by-hand)
>
> Instead of fixing small holes when we fall on them, the aim of this
> ticket is to audit Sage use of `RealIntervalField` (list to be enlarged):
>
> - check that all python builtin functions are overwritten for
> `RealIntervalField` (or work consistently by default).
> - grep the Sage source code and check that `RealIntervalField` is not
> misused.
New description:
{{{
sage: max(RIF(2,3), RIF(1,4)).endpoints()
(2.00000000000000, 3.00000000000000)
}}}
We should check that all python builtin functions are overwritten for
`RealIntervalField` (or work consistently by default).
--
--
Ticket URL: <http://trac.sagemath.org/ticket/15360#comment:10>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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