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

[Stéfan van der Walt]

2009/3/15 David Cournapeau <david at ar.media.kyoto-u.ac.jp>:
>    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 ?

So we move the functionality to filter, let lfilter call filter, and
add a deprecation notice to lfilter?  Sounds good.

Cheers
Stéfan