[Numpy-discussion] Questions about the array interface.
konrad.hinsen at laposte.net
konrad.hinsen at laposte.net
Mon Apr 11 02:30:28 EDT 2005
On Apr 9, 2005, at 18:54, Travis Oliphant wrote:
> No, in moving from the struct modules character codes we are trying to
> do something more platform independent because it is very likely that
> different platforms will want to exchange binary data. IEEE-754 is a
> great standard to build
For data exchange between platforms, i.e. through files and network
connections, XDR is arguably a better choice. It actually uses IEEE for
floats, but XDR libraries provide conversion code for other platforms.
It also takes care of byte ordering.
> an interface around. Data sharing was the whole reason the standard
> emerged and a lot of companies got on board.
I think the main reason was standardization of precision, range, and
operations, to make floating-point code more portable. This has had
moderate success, as 100% IEEE platforms are rare if they exist at all.
>> Another detail to consider is that although most machines use the
>> IEEE representation, hardly any respects the IEEE rules for floating
>> point operations in all detail. In particular, trusting that Inf and
>> NaN will be treated as IEEE postulates is a risky business.
>
> But, this can be handled with platform-dependendent C-code when and if
> problems arise.
Can it? I have faint memories about Tim Peters explaining why and how
handling IEEE in C code is a pain. Anyway, it would be a good idea to
get his opinion on whatever proposal about IEEE before implementing it.
Konrad.
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