FloatArray : puzzled about varying speed
Andreas Raab
andreas.raab at gmx.de
Wed Feb 14 09:58:17 UTC 2007
Herbert König wrote:
> The only thing I can think of is that the Arrays of 150 inputs are
> mainly populated with zeroes and 1 to 10 non zero values. So a lot of
> the coefficients end up as '7.00649232162409e-45'.
>
> Wikipedia says the closest to zero number in 32 Bit float is some
> 1e-38 so maybe the above numbers get a special (and time consuming)
> treatment in the primitives?
It is possible (though require specific testing) that the resulting
floating point values cause underflow or similar fp exceptions and may
be handled specially. Only a well-defined benchmark could tell. But just
out of curiosity, what processor are you running?
Cheers,
- Andreas
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