>
> Hi,
>
> I've just played a bit with Hauke's nesting refactoring fork
> (
https://bitbucket.org/hauke/nesting-refactoring/).
>
> Let me recall that currently expressions are nested by reference that
> enforces the use NestByValue when a function has to return a nested
> _expression_. See for instance adjoint() which returns
> Transpose<NestByValue<CwiseUnaryOp<ei_scalar_conjugate<Scalar>, Derived> >
>>. As you can see this is pretty annoying. In Hauke's fork lightweight
> expressions (i.e., all but Matrix) are automatically nested by value. So
> need for the NestByValue workaround.
>
> So now the question is what about the performances ? Well I tried a very
> simple example:
>
> Vector4f a, b, c, d;
> c = a+b+c+d;
>
> and here are the respective assembly codes generated by g++ 4.3.3