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

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

Getting some small application that (only) depends on NumPy to run on Jython would be a proof of concept.

I looked at the ndarray "interface". Some things look a bit scary... Are all the attributes and methods mentioned on that page public and non-optional?

Currently ojAlgo supports double, BigDecimal, ComplexNumber and RationalNumber elements with the ArrayAnyD class. Are other types required?

How about I create a sandbox version control system (for experimental code) over at http://code.google.com/p/ojalgo/

What do you prefer: Subversion, Git or Mercurial?

/Anders


On 19 apr 2012, at 22:21, B.D. wrote:

> 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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