[SciPy-User] [SciPy-user] Float32 FFT

David Cournapeau cournape@gmail....
Mon Feb 8 09:19:58 CST 2010


On Mon, Feb 8, 2010 at 9:40 PM, Klaus Kopec
<klaus.kopec@tuebingen.mpg.de> wrote:
>
>
> David Cournapeau-3 wrote:
>>
>> It is supported in scipy trunk (upcoming 0.8.0). It is transparent, that
>> is if your input is single precision, the output is as well.
>>
>
> Maybe I am mistaken, but I think that only fft, but not fftn, is capable of
> fixed-point computations. I checked out the current SVN of scipy a couple of
> minutes ago, and a simple test with a float32 array as input returned a
> complex64 array for fft and a complex128 array for fftn.

Note that neither float32 nor float64 are fixed point types - they are
float point. Scipy does not have any fft support for fixed point.

>
> I am not sure, whether this is a bug, wrong use by me, or a not yet
> implemented feature, as the scipy changelog under
> http://projects.scipy.org/scipy/milestone/0.8.0 is not very specific: "fft
> functions can now handle single precision inputs". 'fft' could refer to ALL
> fftpack-functions (=> fftn not doing it would be a bug), or it could really
> just mean the 1D ones (=> fixed point would be a missing feature for
> N-dimensional FFTs).

The double precision support for fftn was a bug, this is now fixed.

David


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