[CLAM] Calling processings before the Do

[David Garcia]

By porting some algorithms from the QMUL lab, i had a question which
response i think is worth to publish more on the users list than in the
developers' one.

I am porting a constant Q transform algorithm that is something similar to
the fft but the bins with are proportional to the bin center frequency, so
that every octave has the same number of bins.

The first, question is that, before any Do i must compute a kernel
(matrix), once i know the configuration parameters. Which should be the
correct place? ConcreteStart? ConcreteConfigure?

The second related question is that this precomputation is done by appying
the FFT to some constant data depending on the configuration. So, how i
should deal this FFT calling before the Do. Should i create one fft object
on configuration time and call Configure-Start-Do-Stop? Is worth, lazy
initialization for the matrix?


Note, another FFT is called currently on the Do but i was thinking on
removing it out and just take an spectrum as parameter from a port.

David.