Dear all,
I’m writing a class for FFT convolution starting from RooFFTConv class.
The part I am struggling with is how it avoids cyclical effects in performing the convolution.
If I look here root.cern.ch/doc/v606/RooFFTCon … tml#l00592
there are three methods “Extend”, “Flat” and “Mirror” to avoid cyclical effects in convolution.
While I quite understand what
Flat and Mirror do, the implementation of extend method seems obscure to me (and “Extend” is the default
one).
Can someone explain in few words what this methods do?
The documentation says:
/// ‘Extend’ means is that the input p.d.f convolution observable range is widened to include the buffer range
but after extending it how is it filled?
thanks,
francesco