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

David david@silveregg.co...
Wed Nov 10 18:53:27 CST 2010

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 ?



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