[IronPython] Pickle bug

[Curt Hagenlocher]

Yes, we should probably change this to use System.Double.ToString('G17')
On Thu, Sep 4, 2008 at 7:41 AM, Christian Muirhead <
christian.muirhead at resolversystems.com> wrote:

> Michael Foord wrote:
>
>> Pickle on IronPython doesn't preserve sufficient information to unpickle
>> floats accurately:
>>
>> CPython:
>>  >>> a = 1 /3.0
>>  >>> import cPickle as pickle
>>  >>> pickle.loads(pickle.dumps(a)) == a
>>
> (Michael meant to say that this was True)
>
>>
>> IronPython:
>>  >>> import cPickle as pickle
>>  >>> a = 1 /3.0
>>  >>> pickle.loads(pickle.dumps(a)) == a
>> False
>>
>> This is actually causing us numerical errors in Resolver One. CPython is
>> actually very careful about its string representation of floats so that this
>> is possible.
>>
>
> I think it's because IP cPickle is relying on the .NET Double.ToString
> which isn't as truthful as cPython's repr.
>
> The issue's covered here:
> http://www.python.org/doc/current/tut/node16.html
>
> xtian
>
>
> --
> Christian Muirhead
> Resolver Systems
> christian.muirhead at resolversystems.com
> We're hiring! http://www.resolversystems.com/jobs/
>
>
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