Wikipedia:Reference desk/Archives/Computing/2016 September 29

= September 29 =

FFT code
Where I get code for FFT?--86.187.172.8 (talk) 01:06, 29 September 2016 (UTC)
 * Fast Fourier Transform points you to Cooley–Tukey FFT algorithm which has some pseudocode.
 * If you want a "ready to use" code, then depending on the programming language it might already have been implemented, for instance in Python there is numpy.fft. Tigraan Click here to contact me 07:04, 29 September 2016 (UTC)
 * FFTW is a good open-source FFT library (if that's what you want). -- BenRG (talk) 08:43, 29 September 2016 (UTC)

Simple receive SMTP
On Windows command line how can I monitor SMTP 127.0.0.1 port 25 for any incoming email sent to it? It doesn't have to do anything fancy except receive the email stream and dump to output. I just want to test if the emails are being sent to it correctly without setting up a full scale email server. The simpler the better. Thanks — Preceding unsigned comment added by 125.141.200.21 (talk) 12:43, 29 September 2016 (UTC)


 * Python's standard library contains a simple smtpd implementation. Doug Hellmann shows an ultra-simple example of using that, with a tiny program here. If you changed the port, and added the line print 'Message              :', data (after the other prints) then you'd be done. -- Finlay McWalter··–·Talk 13:00, 29 September 2016 (UTC)


 * Reading that whole Hellmann article, he has exactly what you want in the DebuggingServer section of his article. -- Finlay McWalter··–·Talk 13:19, 29 September 2016 (UTC)


 * You need a packet sniffer like wireshark. It monitors and logs network traffic and has many options to filter data based on your needs like only log incoming traffic on port 25 etc. It is nontrivial to use but will give you what you need. manya (talk) 05:55, 30 September 2016 (UTC)
 * Why do you need a packet sniffer? A packet sniffer may be useful for debugging a networking issue, but if you want to test an SMTP session you need something to connect to over SMTP. --47.138.165.200 (talk) 19:33, 30 September 2016 (UTC)