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

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

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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