[Numpy-discussion] Numpty FFT.FFT slow with certain samples

[Joseph Codadeen]

Hi,
I am a numpy newbie.
I have two wav files, one that numpy takes a long time to process the FFT. They was created within audacity using white noise and silence for gaps.
my_1_minute_noise_with_gaps.wavmy_1_minute_noise_with_gaps_truncated.wav
The files are very similar in the following way;
1. is white noise with silence gaps on every 15 second interval.2. is 1. but slightly shorter, i.e. I trimmed some ms off the end but it still has the last gap at 60s.
The code I am using processes the file like this;
    framerate, data = scipy.io.wavfile.read(filepath)    right = data[:, 0]    # Align it to be efficient.    if len(right) % 2 != 0:        right = right[range(len(right) - 1)]    noframes = len(right)    fftout = np.fft.fft(right) / noframes    # <<< I am timing this cmd
Using timeit...
my_1_minute_noise_with_gaps_truncated took 30.75620985s to process.my_1_minute_noise_with_gaps took 22307.13917s to process.
Could someone tell me why this behaviour is happening please?
Sorry I can't attach the files as this email gets bounced but you could easily create the files yourself.E.g my last gap width is 59.9995 - 1:00.0005, I repeat this every 15 seconds.My truncated file is 1:00.0015s long, non-truncated is 1:00.0833s long

Thanks.
 		 	   		  
 		 	   		  
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