Re: [eigen] help using foo(const MatrixBase<T>&) with (u * v)

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

Am 12.03.2015 um 21:44 schrieb Daniel Lee:
> It seems to work fine for transpose, for Map, for MatrixXd, but
> here's a minimal example of the problem we're running into with
> products:

Accessing products coefficient-wise is generally not a good idea. If you 
really want to do that, consider calling foo(u.lazyProduct(v),0,0);
If you want to access multiple coefficients from a inside foo, passing 
via (const Ref<const MatrixXd>&) is probably a better idea.

> If I change the #ifdef to an #ifndef, everything works as expected.
> Are we somehow supposed to be setting the EIGEN2_SUPPORT property
> ourselves?  If I do that in the compilation, it works as expected, but
> I get a deprecation warning:

Yes, you can do that, and you can disable the deprecation warning by 
also defining EIGEN_NO_EIGEN2_DEPRECATED_WARNING.
But as the warning says, this will not be possible with Eigen 3.3 anymore.
See this and the pages linked from there:
http://eigen.tuxfamily.org/dox/Eigen2ToEigen3.html


Christoph


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Dipl.-Inf., Dipl.-Math. Christoph Hertzberg
Cartesium 0.049
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