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

[Anders P. <an...@op...>]

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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