python nan != nan

Question

Python 2.7.3 (default, Aug  1 2012, 05:14:39) 
[GCC 4.6.3] on linux2
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>>> x =          


        

Answer 1

The machine code that implements floating point operations handles the result of operations with NaN. For the x86 processor series this is usually achieved using x87 coprocessor instructions, although for earlier x86 processors where an x87 coprocessor was not always present a compiler usually provided emulation code.