Sorry to bother folks, this must be a simple thing - the following code gives me an error, "Incomplete type":

#include <Eigen/Core>

void xx()
{
Eigen::Quaternion<double> qrot;
}

But this does not:

#include <Eigen/Core>

template<typename T>
void xx()
{
Eigen::Quaternion<double> qrot;
}

I'm using Eigen 2.0.3.

CHeers --Kurt

You need to #include <Eigen/Geometry> to have access to Quaternion.