[Scilab-users] Possible error in manual

[Federico Miyara]

Dear All,

In the help information for the FFT function I find that, regarding the 
"inverse" FFT,  fft(x,1), the formula is

         n
x(k) = SUM(a(m)*exp(2*%i*%pi*(m-1)*(k-1)/n)
        m=1

But this is not the inverse FFT since it lacks the required 1/n factor; 
however, fft(fft(a,-1),1) indeed returns a. So the procedure seems to be 
mistakenly described in the help information.

Interestingly, the fftw3 documentation, http://www.fftw.org/fftw3.pdf, 
gives, on page 42, the same formula but it indicates it is an 
unnormalized transform.

Would you please clarify?

Regards,

Federico Miyara





---
El software de antivirus Avast ha analizado este correo electrónico en busca de virus.
https://www.avast.com/antivirus
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.scilab.org/pipermail/users/attachments/20181214/145dfa9e/attachment.htm>