[eigen] separation declaration -- implementation

[Michael Meyer <mjhmeyer@xxxxxxxxx>]

Folks,

What do you think of the idea of taking the implementations out of the header files so we can compile eigen into a library and link against it.

I think it is most elegant to minimize implementations in headers
by all means possible.

The main reason for this request is the compile time (in excess of a minute), probably two minutes on my medium fast laptop.

I am now referring to version 2.0.
There seemed to be files designed to force the instantiation of templates (if I understand the code correctly).

Would it not be better not to do this and instantiate only the templates
you actually need in your project.

Greetings,

Mike