Bug in floating-point addition: is anyone else seeing this?

Diez B. Roggisch deets at nospam.web.de
Wed May 21 17:16:53 EDT 2008


Dave Parker schrieb:
> On May 21, 2:44 pm, "Jerry Hill" <malaclyp... at gmail.com> wrote:
> 
>> My understand is no, not if you're using IEEE floating point.
> 
> Yes, that would explain it.  I assumed that Python automatically
> switched from hardware floating point to multi-precision floating
> point so that the user is guaranteed to always get correctly rounded
> results for +, -, *, and /, like Flaming Thunder gives.  Correct
> rounding and accurate results are fairly crucial to mathematical and
> scientific programming, in my opinion.

Who says that rounding on base 10 is more correct than rounding on base 2?

And in scientific programming, speed matters - which is why e.g. the 
cell-processor shall grow a double-precision float ALU. And generally 
supercomputers use floats, not arbitrary precision BCD or even rationals.


Diez



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