[SciPy-Dev] contribute to scipy.signal

Ralf Gommers ralf.gommers@gmail....
Mon Mar 4 15:04:09 CST 2013


On Fri, Mar 1, 2013 at 7:34 PM, survinder pal <survinderpal@gmail.com>wrote:

> hello...I am working in the area of signal processing.I want to contribute
> to scipy.signal in signal processing and wavelets domain.Suggestions are
> welcome...
>

Hi Survinder, welcome. The first messages from Pauli and me in this thread
may give you some ideas to start with:
http://thread.gmane.org/gmane.comp.python.scientific.devel/17173.

As for wavelets, there's not a lot in Scipy. What's there (see under
Wavelets in http://docs.scipy.org/doc/scipy/reference/signal.html) could
use a critical review and better documentation. PyWavelets has much more
funcitonality, but development seems to have stalled. No idea why or how,
you could contact the author if that project looks interesting.

Cheers,
Ralf



> On Fri, Mar 1, 2013 at 11:30 PM, <scipy-dev-request@scipy.org> wrote:
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>> Today's Topics:
>>
>>    1. Re: Like to contribute to Scipy (Ralf Gommers)
>>    2. Re: Multilinear interpolation (Pablo Winant)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Thu, 28 Feb 2013 21:27:37 +0100
>> From: Ralf Gommers <ralf.gommers@gmail.com>
>> Subject: Re: [SciPy-Dev] Like to contribute to Scipy
>> To: SciPy Developers List <scipy-dev@scipy.org>
>> Message-ID:
>>         <CABL7CQiRi--wN9egVs4wvBFNHGb0=
>> vHJ9z1xDQN6XvJUqb8UxA@mail.gmail.com>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> On Thu, Feb 28, 2013 at 7:39 AM, anand parthasarathy <anandps20@gmail.com
>> >wrote:
>>
>> > Hi ralf,
>> >
>> > Thank you for your reply. I am thinking of making the Scipy.signal
>> module
>> > to have the functions for communication, like communication toolbox in
>> > matlab. We could join and can effectively launch packages including
>> > features like Error correction mechanisms, channel functions etc. will
>> this
>> > be useful ?
>> >
>>
>> Hi Anand, to be honest I think those features are too specialized for
>> Scipy. I don't know of any Python packages with that type of functionality
>> (but I haven't searched and I'm not an expert). Maybe someone else has a
>> good suggestion. You could consider starting a new scikit if you plan on
>> implementing enough functionality to justify that.
>>
>> Cheers,
>> Ralf
>>
>>
>>
>> >
>> > Else can you point me towards any project involving productive results.
>> >
>> >
>> >
>> >
>> >
>> >
>> > Regards,
>> > Anand parthasarathy
>> >
>> > On Mon, Feb 25, 2013 at 2:11 AM, Ralf Gommers <ralf.gommers@gmail.com
>> >wrote:
>> >
>> >>
>> >>
>> >>
>> >> On Tue, Feb 19, 2013 at 8:44 AM, anand parthasarathy <
>> anandps20@gmail.com
>> >> > wrote:
>> >>
>> >>> Hi,
>> >>>
>> >>> I would like to start contribute to Scipy - signal processing module.
>> I
>> >>> have been using MATLAB for a very long time, to the extend that i have
>> >>> implemented many signal processing algorithms targeting the
>> applications in
>> >>> the field of Communications & wireless PHY Layer .
>> >>>
>> >>>  I am currently a Research Intern at Centre of Excellence in Wireless
>> >>> Technology (CEWiT), India. I am so much fascinated by Scipy and
>> though i am
>> >>> new to python, i started love to code in python environment.
>> >>>
>> >>> Since this field is like a ocean , i would like to get suggestions
>> from
>> >>> you guys on this like where to start , and after decided with a
>> specific
>> >>> part to work on , i will start and contribute many things to Scipy to
>> the
>> >>> extend that i can.
>> >>>
>> >>
>> >> Hi Anand, welcome! The signal module certainly could use your
>> >> contributions.
>> >>
>> >> The same question you're asking was asked about a month ago by someone
>> >> else, please have a look at this thread:
>> >> http://thread.gmane.org/gmane.comp.python.scientific.devel/17173 . It
>> >> contains a few ideas and pointers for getting started. If you have
>> ideas
>> >> for new algorithms/functionality to contribute, I recommend that you
>> first
>> >> discuss them on this mailing list to make sure the code you write will
>> be a
>> >> good fit for scipy.
>> >>
>> >> If you have more specific questions later, please don't hesitate to
>> ask.
>> >>
>> >> Cheers,
>> >> Ralf
>> >>
>> >>
>> >>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> Regards,
>> >>> Anand Parthasarathy
>> >>>
>> >>>
>> >>>
>> >>> _______________________________________________
>> >>> SciPy-Dev mailing list
>> >>> SciPy-Dev@scipy.org
>> >>> http://mail.scipy.org/mailman/listinfo/scipy-dev
>> >>>
>> >>>
>> >>
>> >> _______________________________________________
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>> >
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>> ------------------------------
>>
>> Message: 2
>> Date: Fri, 01 Mar 2013 11:58:27 +0100
>> From: Pablo Winant <pablo.winant@gmail.com>
>> Subject: Re: [SciPy-Dev] Multilinear interpolation
>> To: scipy-dev@scipy.org
>> Message-ID: <513089D3.7010607@gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> So I have updated the tempita template using fused types. I also
>> included code generation helper functions in python blocks.
>>
>> I found a problem with the template generation engine
>> (
>> https://groups.google.com/forum/?fromgroups=#!topic/paste-users/bwrf6xPhIjo
>> ).
>> Basically, functions defined in python blocks cannot depend upon each
>> other. In particular, they cannot be recursive. I avoided the problem by
>> defining a dummy function but this is of course not very elegant.
>>
>> On the pyx side:
>> - I included a "with nogil, parallel():" instruction but I am not sure
>> if it has enabled any parallel calculation at all. Cpu usage seems to
>> rely on one core only.
>> - By looking at the generated C file, I suspect there is still a small
>> cython overhead. I see conditional branches inside the loop while there
>> should be none.
>> - Maybe I should not be using memoryviews and use arrays of pointers
>> instead inside the loop ? Then would it be enough to pass memoryviews as
>> arguments in order to ensure data continuity ?
>> - Performances are not so bad if I compare to matlab. I tried to
>> evaluate a function defined over a [4,3,5,6] 4d-grid on 10000000 random
>> points and I got 0.2s vs 1.4s for matlab's interpn(...,'linear*'). Of
>> course this is to be taken with a grain of salt and I think it could
>> still be improved a bit.
>>
>>
>>
>> On 25/02/2013 21:19, Pauli Virtanen wrote:
>> > 25.02.2013 22:04, Pablo Winant kirjoitti:
>> > [clip]
>> >>> - The code assumes C-contiguous arrays, but does not check for it.
>> >> right
>> > Note that you can make Cython to check for this, the syntax is
>> > sometype[::1] or sometype[:,::1] for multidim (see below).
>> >
>> > [clip]
>> >>> You can use fused types instead of templating; the end result is the
>> same,
>> >>> but Cython takes care of picking the correct routine.
>> >>>
>> >> I tried it but I didn't see how to do it. I would like to do define a
>> >> function like
>> >>
>> >> def function(ndarray[fused_type, ndim=2]):
>> >>       ...
>> >>       cdef fused_type internal_variable
>> >>       ...
>> >>       return something
>> > The syntax for these arrays is
>> >
>> >       cdef fused number_t:
>> >           double
>> >           double complex
>> >
>> >
>> >       def my_function(fused_type[:,:] arg)
>> >           ...
>> >
>> > I think it doesn't work with the (old) np.ndarray syntax.
>> >
>>
>>
>>
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>> End of SciPy-Dev Digest, Vol 113, Issue 1
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>
>
>
> --
> regards
>
> Survinder Pal
> M.Tech(AIE)
> CSIR-CSIO Chandigarh
> survinderpal@csio.res.in
> 9569868960
>
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