On Wed, 21 Nov 2007, Frank Barknecht wrote:
Actually what comes into the rfft object are two values as well: One is the usual signal amplitude visible as a patch cord, and the other is: time!
I don't think that you can think of the time dimension as a value of what comes into the object: I'd say that it is the index of the amplitude. Only amplitude is transmitted: time is part of the structure of the actual transmission, not the content.
Anyway, that idea would make the complex fft take three inputs: real, imaginary, and time.
What [rfft~] does is assume a zero imaginary part. There's a special version of the FFT algorithm that is only a slight optimisation because it can assume that the imaginary input is zero. [rifft~] can assume that the imaginary output is zero or maybe just not wanted, so it can make different optimisations.
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