#8896: 0.0000000000000000000000000000 is parsed completely differently than
1.0000000000000000000000000000 for no good reason
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Reporter: was | Owner: AlexGhitza
Type: defect | Status: needs_info
Priority: minor | Milestone: sage-4.7.1
Component: basic arithmetic | Keywords:
Work_issues: | Upstream: N/A
Reviewer: Mariah Lenox | Author: Robert Bradshaw
Merged: | Dependencies:
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Comment(by jdemeyer):
Replying to [comment:26 robertwb]:
> Replying to [comment:25 jdemeyer]:
> > In my opinion, this ticket is a huge can of worms and a bad idea. I
don't see any mathematically consistent reason who 0.0 '''should''' be
treated differently than 0.0000000000000.
>
> It's exactly the same reason that 1.0 is treated differently than
1.0000000000000000000000. The (value-preserving) trailing zeros indicate
higher precision.
It is absolutely ''not the same'' because with non-zero numbers only
digits '''after''' a non-zero digit contribute to the precision. Indeed,
`0.437` and `0.00000000000437` have exactly the same precision.
> Because otherwise there's now way to write a high-precision zero (in
fact I can't think of any other interpretation of a large number of
trailing zeros).
Well, you can always do:
{{{
sage: zero = RealField(1000)(0)
sage: zero.prec()
1000
}}}
An other way to demonstrate the problem with this patch is that truncating
decimal numbers (i.e. removing digits from the right) can ''increase'' the
precision, which is very unlogical::
{{{
sage: (0.000000000000000000001234567890123456789).prec()
67
sage: (0.00000000000000000000123456789012345678).prec()
64
sage: (0.000000000000000000001).prec()
53
sage: (0.00000000000000000000).prec()
74
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8896#comment:28>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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