[SciPy-Dev] Proposal: calling signal.lti object returns transfer function value
Tue Jul 23 07:09:43 CDT 2013
On 7/23/13, Juan Luis Cano <firstname.lastname@example.org> wrote:
> On 07/20/2013 05:39 PM, Ralf Gommers wrote:
>> On Tue, Jul 16, 2013 at 4:49 PM, Juan Luis Cano <email@example.com
>> <mailto:firstname.lastname@example.org>> wrote:
>> Hello all,
>> I've been trying the scipy.signal module lately for some easy
>> things and
>> I had an idea, but I thought it would be better to bring it up in the
>> mailing list before filing a PR on GitHub.
>> My proposal is to implement the __call__ method on signal.lti
>> objects so
>> it returns the value on the transfer function.
>> I took the idea from the `bode` function. This line:
>> y = numpy.polyval(sys.num, jw) / numpy.polyval(sys.den, jw)
>> could be moved to signal.lti.__call__, and then in `bode` write
>> y = sys(jw)
>> The detail is trivial (so is the implementation) but I think it
>> would be
>> a useful thing. What do others think? Shall I open a pull request?
>> Not sure, is writing
>> y = lti_sys(jw)
>> instead of
>> jw, y = lti_sys.freqresp(jw)
>> clearer and umambiguous? It may make sense, but would be good to get
>> the opinion of some users on this.
> I am sorry but I was unaware of the freqresp function, probably it's the
> clearest way. Maybe it should be used in the `bode` function too.
There was some work on bode and freqresp earlier this year. The
latest version of `bode` uses `freqresp`:
> Juan Luis Cano
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