RotationQuaternion: _C doesn't get set on "set()" call? (No real problem, just wondering)

[PeterMuehlfellner]

Probably this is intentional, I just ran into it while doing some checks.

The line is:

void set( const Eigen::Vector4d & q){ _q = q; _p_q = q; }

would have expected something like:

void set( const Eigen::Vector4d & q){ _q = q; _p_q = q; _C = sm::kinematics::quat2r(_q);}