Re: [eigen] Rigid Transformations in eigen: discussion thread

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

2009/9/18 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>:
> maybe it is still worth keeping Scalar so that one can easily declare
> a DualQuaternion:
>
> DualQuaternion<float> dq;
>
> For an example of this technique have a look at my auto-diff module in
> unsupported/.

OK

>
> Finally, do you think Quaternion should be implemented this way as
> well ? I mean for DualQuaternion these two operators are really useful
> (unlike for Quaternion where slerp is really what you should use), and
> since dualquat are larger high efficiency require ET (again unlike
> Quaternion).

I think it's worth doing the same for Quaternion for consistency. If
DualQuaternion has an operator+, then Quaternion should too. Rohit
mentioned that nlerp is also wanted for Quaternion. Then there is the
question of whether it should return by value or using your trick,
well i think that your trick brings more benefits (e.g. mapping
expressions) so once we have the DualQuaternion impl it's worth
porting to Quaternion... also it's a more consistent API: if
DualQuaternion can Map any xpr, so should Quaternion.

Benoit