Re: [ojAlgo-user] Interface analogous to Numpy?

[B.D. <ab...@ma...>]

Dear Mr. Peterson,

> Don't talk too much - just do it. Start with the most simple case.

yes, you're right. I think this is a nice collection of simple unit tests for
me: http://www.scipy.org/Numpy_Example_List

See you later,
  B.D.
  

Anders Peterson wrote:
> Let's call it Jumpy...
> 
> Since I'm not a python/jython/numpy/scipy user I think someone else should take the lead here.
> 
> Don't talk too much - just do it. Start with the most simple case.
> 
> I'm definitely interested in ways to make ojAlgo more useful.
> 
> /Anders
> 
> 
> On 19 apr 2012, at 15:39, Stefan Richthofer wrote:
> 
>> Hello together,
>> I also often thought about the idea to have a numpy-substitute for java, but always feared the enormous effort related to it.
>> 
>> Be aware of the high Potential of the idea. 
>> 
>> Having a numpy substitute in java would enable a huge amount of scientific python-code to run directly in java via jython (maybe with a slight modification of the imports).
>> 
>> Jython's main issue keeping it from being very useful is, that it does not support external (native) libraries written for Python.
>> 
>> I regard numpy as one of the most important of these and I believe, that a significant amount of scientific python-code has numpy as the only non-python-core-dependency and thus could run via jython, if there was a numpy for java.
>> 
>> Maybe you could consider a cooperation with the jython-developers at http://www.jython.org ...?
>> It should be highly in their interest to have a numpy implementation for java.
>> 
>> 
>> Greetings
>> 
>> Stefan
>> 
>> 
>> 
>> -------- Original-Nachricht --------
>>> Datum: Thu, 19 Apr 2012 13:56:49 +0200
>>> Von: Anders Peterson <an...@op...>
>>> An: oja...@li...
>>> Betreff: Re: [ojAlgo-user] Interface analogous to Numpy?
>> 
>>> Short anser is yes, but you have to be more specific regarding what you
>>> want/need and willing to do some of the work yourself.
>>> 
>>> ojAlgo has multi/any-dimensional arrays:
>>> 
>>> http://ojalgo.org/generated/org/ojalgo/array/ArrayAnyD.html
>>> 
>>> Frankly I don't really know what to do with them. I tend to only use 1- or
>>> 2-dimensional data structures. I created them because they were a
>>> generalization of what I needed that *could* become useful.
>>> 
>>> I guess the various MatrixStore implementations and the
>>> MatrixStore.Builder does much of what you want, but only for 2-dim arrays (and with wrong
>>> syntax).
>>> 
>>> http://ojalgo.org/generated/org/ojalgo/matrix/store/MatrixStore.html
>>> http://ojalgo.org/generated/org/ojalgo/matrix/store/MatrixStore.Builder.html
>>> 
>>> In ojAlgo the description of the array shape/structure is fixed as defined
>>> in AccessUtils
>>> 
>>> http://ojalgo.org/generated/org/ojalgo/access/AccessUtils.html
>>> 
>>> Would that need to be changed? (I hope not.)
>>> 
>>> /Anders
>>> 
>>> 
>>> On 19 apr 2012, at 11:35, B.D. wrote:
>>> 
>>>> Dear developers,
>>>> 
>>>> I'm primarily interested in Machine Learning and Data analysis. Thanks
>>> for the
>>>> good work, I appreciate the ojAlgo library very much! However, most new
>>>> algorithms and applications in this field are still written in Python
>>> for
>>>> Numpy/Scipy, not Java. I just had an idea:
>>>> 
>>>> If one could offer classes/interfaces in pure Java with similar
>>> functionality
>>>> and names as in
>>>> 
>>>> http://docs.scipy.org/doc/numpy/reference/ ,
>>>> 
>>>> in particular ndarray
>>>> 
>>>> http://docs.scipy.org/doc/numpy/reference/arrays.ndarray.html
>>>> 
>>>> (e.g. strides in matrices and vectors, transposition, reshaping of
>>> matrices as
>>>> a view without copying, many views on the same matrix data), then one
>>> could
>>>> rather easily translate Python programs using Numpy to pure Java without
>>>> reinventing the wheel and offer the excellent Python software for Java
>>> under
>>>> the same license as the original.
>>>> 
>>>> There are syntax limitations in Java, so
>>>> 
>>>> A[2:5, :]
>>>> 
>>>> would have to be translated to some intutive name or even a crazy
>>> mnemonic like
>>>> 
>>>> A.viewI_c_icI(2, 5)
>>>> 
>>>> (I = [ or ],
>>>> i = comma,
>>>> c = colon,
>>>> _ = slots for the arguments).
>>>> 
>>>> What do you think?
>>>> 
>>>> Best regards
>>>> B.D.
>>>> 
>>>> 
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>> 
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>> 
> 
> 
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