Re: [eigen] Eigen "views"

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

On 16.08.2011 08:48, Gael Guennebaud wrote:
> I confirm what Benoit said, this has yet to be implemented and this is
> probably the most wanted feature!
>
> API-wise, what about simply overloading operator(). For vectors:
>
> VectorXf v1, v2;
> VectorXi indices;
>
> v2 = v1(indices);
>
> And for matrices:
>
> MatrixXf m1, m2;
> VectorXi indices1, indices2;
>
> m2 = m1(indices1,indices2);
> m2 = m1(Eigen::All,indices2);
> m2 = m1(indices1,Eigen::All);

Yes, I think this looks as close as one can get to Matlab-syntax (not 
that this is a requirement, but it's definitely not a bad thing).

> "m1(indices1)" would be forbidden for matrices.
>
> Maybe the constant "All" is too intrusive when someone do using
> namespace Eigen ??

It definitely should be a separate type, not a constant, similar 
problem/solution as in resize.
In principle it would be nice to reuse the same type, though I agree 
that NoChange, might be counter-intuitive here.

Christoph

--
----------------------------------------------
Dipl.-Inf. Christoph Hertzberg
Cartesium 0.051
Universität Bremen
Enrique-Schmidt-Straße 5
28359 Bremen

Tel: (+49) 421-218-64252
----------------------------------------------