Re: [eigen] ISO C++ working groups on Linear Algebra / Machine Learning

[Christian Mayer <mail@xxxxxxxxxxxxxxxxx>]

Am 16.02.19 um 16:20 schrieb Francois Fayard:
> 
>> A * ( D +  C * E * B + B * E * C)
> 
> I personally never came across some code where such a complex operations
> occur. Using operations such as + and * allows code doing such
> operations being easier to read but also needs the complexity of
> template meta-programming to avoid temporaries. This is the road that
> has been chosen by Eigen, Blaze and Armadillo. Eigen does a pretty good
> job at doing that.
> 
> I just believe that if we need to have something in the C++ standard
> library, it does not have to copy those libraries. Eigen already solve a
> problem which is allowing users to write “Matlab-like code” in C++. I
> just want to stress out that there are some people out there who needs
> another problem to be solved.

There's also a big demand on the other side of the useage spectrum:

For computer graphics or any movements in the real world (physics
simulation, autonomous vehicles, ...) only fixed sized matrices and
vectors up to dimension 4 are needed.
And these use cases also benefit from Eigen - and would also benefit a
lot when the C++ standard would have a way to handle these data types
efficiently (including a transparent interface to e.g. OpenGL)

As important as any use case is, please don't forget the other ones.

(And, I'd guess, fixed size up to 4 dimensional linear algebra is used
far more often than tensors - measured by the amount or programmers,
applications as well as users...)

Just my 2ct,
Christian