Blaze aims to do something like that; to make the notion of an array and how it stores it's data far more flexible. But if it isn't a single strided ND array, it isn't numpy. This concept lies at its very heart; and for good reasons I would add. -----Original Message----- From: "Benjamin Root" <ben.root@ou.edu> Sent: 8-9-2014 19:00 To: "Discussion of Numerical Python" <numpy-discussion@scipy.org> Subject: Re: [Numpy-discussion] Generalize hstack/vstack --> stack; Blockmatrices like in matlab Btw, on a somewhat related note, whoever can implement ndarray to be able to use views from other ndarrays stitched together would get a fruit basket from me come the holidays and possibly naming rights for the next kid... Cheers! Ben Root On Mon, Sep 8, 2014 at 12:55 PM, Benjamin Root <ben.root@ou.edu> wrote: A use case would be "image stitching" or even data tiling. I have had to implement something like this at work (so, I can't share it, unfortunately) and it even goes so far as to allow the caller to specify how much the tiles can overlap and such. The specification is ungodly hideous and I doubt I would be willing to share it even if I could lest I release code-thulu upon the world... I think just having this generalize stack feature would be nice start. Tetris could be built on top of that later. (Although, I do vote for at least 3 or 4 dimensional stacking, if possible). Cheers! Ben Root On Mon, Sep 8, 2014 at 12:41 PM, Eelco Hoogendoorn <hoogendoorn.eelco@gmail.com> wrote: Sturla: im not sure if the intention is always unambiguous, for such more flexible arrangements. Also, I doubt such situations arise often in practice; if the arrays arnt a grid, they are probably a nested grid, and the code would most naturally concatenate them with nested calls to a stacking function. However, some form of nd-stack function would be neat in my opinion. On Mon, Sep 8, 2014 at 6:10 PM, Jaime Fernández del Río <jaime.frio@gmail.com> wrote: On Mon, Sep 8, 2014 at 7:41 AM, Sturla Molden <sturla.molden@gmail.com> wrote: Stefan Otte <stefan.otte@gmail.com> wrote:
stack([[a, b], [c, d]])
In my case `stack` replaced `hstack` and `vstack` almost completely.
If you're interested in including it in numpy I created a pull request [1]. I'm looking forward to getting some feedback!
As far as I can see, it uses hstack and vstack. But that means a and b have to have the same number of rows, c and d must have the same rumber of rows, and hstack((a,b)) and hstack((c,d)) must have the same number of columns. Thus it requires a regularity like this: AAAABB AAAABB CCCDDD CCCDDD CCCDDD CCCDDD What if we just ignore this constraint, and only require the output to be rectangular? Now we have a 'tetris game': AAAABB AAAABB CCCCBB CCCCBB CCCCDD CCCCDD or AAAABB AAAABB CCCCBB CCCCBB CCCCBB CCCCBB This should be 'stackable', yes? Or perhaps we need another stacking function for this, say numpy.tetris? And while we're at it, what about higher dimensions? should there be an ndstack function too? This is starting to look like the second time in a row Stefan tries to extend numpy with a simple convenience function, and he gets tricked into implementing some sophisticated algorithm... For his next PR I expect nothing less than an NP-complete problem. ;-) Jaime -- (\__/) ( O.o) ( > <) Este es Conejo. Copia a Conejo en tu firma y ayúdale en sus planes de dominación mundial. _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion