[SciPy-User] Single precision FFT insufficiently accurate.

Sturla Molden sturla@molden...
Mon Jun 28 09:24:11 CDT 2010


Den 28.06.2010 13:21, skrev Sebastian Haase:
> What size of error are talking about anyway .. ?
> Personally I would leave it in,
>    

Leave in FFT code that produces 5% relative error?

Single-precision is not the solution to memory issues anyway. Get a 64 
bit system and buy more RAM. Buying RAM is far cheaper than even 
re-coding for single precision, if you value the time spent coding, not 
to mention that the result is far more accurate.

Single-precision used to be faster than double precision some 30 years 
ago. And on 8 bit and 16 bit computers, memory did matter more. For 
example on a 16 bit CPU with power-of-2 FFT, the largest FFT size would 
be just 2096 in double precision. With single precision you could get 
4096 ... Oorah! Today we rearely see those issues. Python does not even 
support single precision.

Sturla


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