Multidimensional arrays indexing and slicing syntax is finally added [1] (thanks to Kenji Hara). So it was a good cause to update my multidimensional arrays library implementation and add support for the new syntax. So here we are: [2].

Also should we add it to the standard library?

[1] https://github.com/D-Programming-Language/dmd/pull/443
[2] http://denis-sh.bitbucket.org/unstandard/unstd.multidimarray.html

-- 
Денис В. Шеломовский
Denis V. Shelomovskij

+100



On Monday, 17 March 2014 at 17:39:41 UTC, Denis Shelomovskij wrote:
> Multidimensional arrays indexing and slicing syntax is finally added [1] (thanks to Kenji Hara). So it was a good cause to update my multidimensional arrays library implementation and add support for the new syntax. So here we are: [2].
>
> Also should we add it to the standard library?
>
> [1] https://github.com/D-Programming-Language/dmd/pull/443
> [2] http://denis-sh.bitbucket.org/unstandard/unstd.multidimarray.html

On Mon, Mar 17, 2014 at 09:39:40PM +0400, Denis Shelomovskij wrote:
> Multidimensional arrays indexing and slicing syntax is finally added [1] (thanks to Kenji Hara). So it was a good cause to update my multidimensional arrays library implementation and add support for the new syntax. So here we are: [2].
> 
> Also should we add it to the standard library?
> 
> [1] https://github.com/D-Programming-Language/dmd/pull/443
> [2] http://denis-sh.bitbucket.org/unstandard/unstd.multidimarray.html
[...]

Let's do it! Put it up for review!

I almost gave up hope that this day would come, but this morning I looked at the dmd commit log and saw Kenji's pull was merged. You couldn't believe how happy I was. Finally, sane multidimensional array support!!


T

-- 
Almost all proofs have bugs, but almost all theorems are true. -- Paul Pedersen

Good news and kudos to Kenji.

And yes, I think that a matrix / linear algebra library, as well as NumPy-style ND-Arrays are great candidates for future Phobos modules.

We've done a good bit of work with matrices at my workplace (EMSI), so I bet someone here could find time to contribute a bit. As a start, we've got some basic BLAS and MKL bindings that we really should clean up and get into Deimos.

On Monday, 17 March 2014 at 17:39:41 UTC, Denis Shelomovskij wrote:
> Multidimensional arrays indexing and slicing syntax is finally added [1] (thanks to Kenji Hara). So it was a good cause to update my multidimensional arrays library implementation and add support for the new syntax. So here we are: [2].
>
> Also should we add it to the standard library?
>
> [1] https://github.com/D-Programming-Language/dmd/pull/443
> [2] http://denis-sh.bitbucket.org/unstandard/unstd.multidimarray.html

Jared Miller:

> And yes, I think that a matrix / linear algebra library, as well as NumPy-style ND-Arrays are great candidates for future Phobos modules.

I suggest to not put such library in Phobos before few years of usage in the wild.

Bye,
bearophile

I looked to the doku-page and expected to see, how some basic
matrix-operations could be performed.
Like e.g. (basic syntax) this:

 Dim  a(10,12)
 a(3,4) = 7
 a(i,j) = a(j,i) * 12

Instead I found exotic assignments and calculations.
Did I expect the wrong thing?

17.03.2014 21:39, Denis Shelomovskij пишет:
> Multidimensional arrays indexing and slicing syntax is finally added [1]
> (thanks to Kenji Hara). So it was a good cause to update my
> multidimensional arrays library implementation and add support for the
> new syntax. So here we are: [2].
>
> Also should we add it to the standard library?
>
> [1] https://github.com/D-Programming-Language/dmd/pull/443
> [2] http://denis-sh.bitbucket.org/unstandard/unstd.multidimarray.html
>

An important note:
My proposal is just a sliceable multidimensional array implementation, a try to provide the same effort we have for simple arrays for multidimensional ones. It isn't aimed to be a dedicated matrix / linear algebra module.


-- 
Денис В. Шеломовский
Denis V. Shelomovskij

On Tue, Mar 18, 2014 at 01:55:31AM +0400, Denis Shelomovskij wrote:
> 17.03.2014 21:39, Denis Shelomovskij пишет:
> >Multidimensional arrays indexing and slicing syntax is finally added [1] (thanks to Kenji Hara). So it was a good cause to update my multidimensional arrays library implementation and add support for the new syntax. So here we are: [2].
> >
> >Also should we add it to the standard library?
> >
> >[1] https://github.com/D-Programming-Language/dmd/pull/443
> >[2] http://denis-sh.bitbucket.org/unstandard/unstd.multidimarray.html
> >
> 
> An important note:
> My proposal is just a sliceable multidimensional array implementation,
> a try to provide the same effort we have for simple arrays for
> multidimensional ones. It isn't aimed to be a dedicated matrix /
> linear algebra module.
[...]

It will be a good low-level module that will allow a linear algebra module to be built on.

I am against the idea of conflating multidimensional arrays with matrices; the operations and interpretations are not the same, and it leads to poor designs (I've tried it before, and the results were not so good). Better have a general multidimensional array with per-element operations, and then build matrix algebra as a separate module by using multidimensional array as underlying storage implementation.


T

-- 
Answer: Because it breaks the logical sequence of discussion. / Question: Why is top posting bad?

> It will be a good low-level module that will allow a linear algebra
> module to be built on.

Agreed.  In fields like graphics and computer vision, large multidimensional arrays aren't always matrices/tensors in the linear algebra sense.  And it's always possible to specialize.  NumPy got this right.

18.03.2014 1:35, Christof Schardt пишет:
> I looked to the doku-page and expected to see, how some basic
> matrix-operations could be performed.
> Like e.g. (basic syntax) this:
>
>   Dim  a(10,12)
>   a(3,4) = 7
>   a(i,j) = a(j,i) * 12
>
> Instead I found exotic assignments and calculations.
> Did I expect the wrong thing?

Sorry for that. Do you mead there is a lack of simple indexing examples or lack of some matrix functionality? The latter case is if you meant "transpose and multiply by 12" with `a(i,j) = a(j,i) * 12`.

-- 
Денис В. Шеломовский
Denis V. Shelomovskij