[SciPy-User] which FFT, convolve functions are the fastest one?

braingateway braingateway@gmail....
Thu Nov 11 02:35:57 CST 2010


David :
> On 11/11/2010 08:41 AM, LittleBigBrain wrote:
>   
>> Hi everyone,
>>
>> I found lots of implement of FFT and convolve
>> numpy.fft
>> scipy.fftpack
>> scipy.signal.fft (from the source, it seems all import from scipy.fftpack?)
>>     
>
> scipy.fftpack is faster than numpy.fft, scipy.signal.fft is the same as 
> scipy.fftpack as you noticed.
>
>   
>>> From the source, it looks like fftpack.convolve and signal.fftconvolve
>>>       
>> all based on fftpack, then what is the difference between them?
>>     
>
> Different APIs (mostly for historical reasons AFAIK)
>
>   
>> I take a glance at the lfilter.c, surprisingly it is a completely
>> naive implement via polynomial function. I hope I am wrong about this.
>>     
>
> No, you're right, it is a straightforward implementation of time-domain 
> convolution. Note that it supports types beyond what LAPACK would 
> support (integers, long double, python objects), but LAPACK has no 
> convolution function anyway, so I am not sure to understand what you are 
> refering to ?
>   
Oh, sad! Because, MKL seems to have this routine, so I thought usual 
LAPACK has it. MATLAB conv() and filter() based on this, making it much 
faster.


> cheers,
>
> David
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>   

Thanks a lot!

LittleBigBrain
>   


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