Re: [eigen] Future for Eigen 2.0

2014/1/16 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>

On Thu, Jan 16, 2014 at 4:57 PM, Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On 16.01.2014 16:38, Benoit Jacob wrote:

What I don't know --- it is for current maintainers to tell --- is how much
maintainance cost is incurred by Eigen3's compatibility modes. If it were
significant, it could make sense to remove these modes from Eigen trunk and
communicate in the documentation that these modes are only available up to
version e.g. 3.2 and therefore people porting from Eigen 2 are invited to
first port to Eigen 3.2 before moving on to newer Eigen versions.

I think for pure maintenance the cost is neglectable. Problems might be bigger refactorings like the new _expression_ evaluation (but that's mostly a question Gael should answer).

yes, maintaining this compatibility layer after the _expression_ template refactoring will be a high cost, so for me it's pretty clear it has to be removed for 3.3.

That makes sense. Thanks a lot for the evaluator work! It is many times worth the loss of Eigen2 compatibility modes, which were meant to go eventually anyway. Just make sure to communicate clearly that people who need the eigen2->3 porting path, need to use Eigen 3.2 at first.

Benoit