[Numpy-discussion] Unexpected float96 precision loss

Christopher Barker Chris.Barker@noaa....
Thu Sep 2 11:06:23 CDT 2010


Charles R Harris wrote:
>>> So if you write "float96(0.0001)", the result is not the float96 number
>>> closest to 0.0001, but the 96-bit representation of the 64-bit number
>>> closest to 0.0001.
...

>> but wouldn't it be better to exactly handle strings since those can be
>> converted exactly, which is what the user wants/expects?
>>
> Well, yes. But then we would need to write our own routines for the
> conversions...

The mechanism used in fromstring() and fromfile() (when used for text 
parsing) looks like it's designed to support this -- i.e. the actual 
string parsing is done be a function provided by the datatype.

I haven't looked to see if there is anything special there for float96.

Does the clib for a compiler that provides a float64 also provide an 
atof() function that supports it? Its seems that it should.

-Chris



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