[SciPy-dev] #880: lfilter, variable number of output

[David Cournapeau]

Hi,

    A user of scipy.signal.lfilter reported a bug in it, which I fixed,
but he also raised an interesting point concerning the variable number
of output in lfilter. I think always outputting the final values of the
delay line is better as well, but we can't change it wo breaking lfilter
API. I first thought about adding a lfilter2, but the name is a bit
misleading - and I also noticed that filter is not taken (which is the
name of this functionality under matlab).
    What about adding a filter function which is like lfilter, but
always return zf ?

cheers,

David