Re: Apache Portable Runtime
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- Subject: Re: Apache Portable Runtime
- From: Miles Bader <miles@...>
- Date: 2007年3月14日 22:55:43 +0900
"Jérôme VUARAND" <jerome.vuarand@gmail.com> writes:
>> Doesn't this run into problems with precision if "float" is the basic
>> number type? Actually if numbers are floats it seems that any
>> unix-like date representation will have problems...
>
> The problem already is also present with doubles. I made the following
> quick test, and it appears that about half numbers between one and one
> million get rounding errors with the conversion we are talking about
> (an integer in microseconds to a float in seconds).
Hmm, well since common fractional time units aren't exactly
representable with base-2 floats, you'd inevitably get some kind of
small error. I don't know if that would actually be a practical problem
using doubles and representing typical time intervals, but as soon as
you try to use floats or represent absolute times, I think things get
pretty dicey...
-Miles
--
`Cars give people wonderful freedom and increase their opportunities.
But they also destroy the environment, to an extent so drastic that
they kill all social life' (from _A Pattern Language_)