# [erlang-questions] [Erlang-Question] Is Erlang good for Matrix manipulation and AI related algorithms

Peer Stritzinger peerst@REDACTED
Wed Nov 9 20:08:03 CET 2011

```On Wed, Nov 9, 2011 at 6:31 AM, Barco You <barcojie@REDACTED> wrote:
> As known, Erlang is born with inherent distributed-computing properties and
> is good for lists manipulation, but currently I'm encountering a problem
> that I don't know how to do with Erlang in an efficient way.

There is no code to see yet but you might watch

https://bitbucket.org/peerst/numerlang/wiki/Home

I'm working on a ndimarray module in my spare time, my plans are under
the above link.

> I hope to build a cubic matrix with I x J x K dimension (I,J,K are integers
> and >= 2), for which the origin (index [1,1,1], or [0,0,0] for c/java/lisp)
> is assigned with an initial value 1, and then the initial value is
> unidirectionally message-passed to adjacent nodes.

Are you meaning message passing in the Erlang sense?  This seems a bit
overkill then.

> Every node gets a value
> that is the sum of afferent messages and continue to pass its value deeper
> forward, until the far-most node (with index [I,J,K]) gets a value. Taking a
> 2x2x2 dimensional scenario as an example (in the attached picture, the
> vertices of the cube represent the nodes of the matrix), we will get a final
> matrix as [ [ [1,1], [1,2] ], [ [1,2], [2,6] ] ].

Your description of the algorithm confuses me, can't you describe this
more in the sense of matrix operations than message passing?

It is unclear how the timing of your messages should be? Some kind of
synchronous?  All at once? Asynchronous in whatever order?

> To implement this, I'll have two functions: gen_cubic([I,J,K]) -> list().
>  get_value([i,j,k], Cubic::list()) -> number().
> BTW: I heard of that Lisp is good for this kind of matter, but when I tried
> to learn List yesterday I found it's so hard to read and the syntax is not
> so natural as Erlang.

Be aware that syntax is secondary, semantics is the important
differentiation factor.

If you want to do this with lists does this mean you first want to
distribute the "messages" in the direction of the innermost dimension
etc?

You need to give us more information what you *really* want to achieve
by this algorithm.  Maybe its the wrong algorithm for doing this in
erlang.  As you described it I at least can't understand what exactly
you want to achieve with this.

Anything that can be done in Lisp *except* macros can usually be done in Erlang.

> So, if someone have more time, please give your
> insights comparing these two language. I would appreciate that.

Lisp and Erlang are similar up to a point (there is even a Lisp
flavored Erlang = LFE front-end).
Lisp lists are identical to Erlang lists.
Lisp macros are not available in Erlang syntax.
Erlang has pattern matching, very lightweight processes and message
passing that Lisp doesn't have.

But on the other hand: The way Lisp is programmed is that it turns
into whatever domain specific language your problem needs as you go
along.  So in theory at least Lisp can be made to do all these things.
What can't be done easily in Lisp is getting the performance,
low-latency and robustness characteristics of Erlang.

My suggestion: learn both, pick the one you like most first.  And when
you know Lisp and Erlang, learn another language and so on ...

-- Peer

```

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