[BUG] The constructor of DQ does not work for pure dual quaternions

Bug description

It should be possible to create a DQ object from an Eigen vector with the pure dual quaternion coefficients, that is, a vector of size 6. In fact, the library does not complain when creating a DQ from a vector of size 6. However, instead of creating a pure dual quaternion, it creates a DQ object with the first 6 elements equal to the elements of the vector, that is q(0) + q(1)i + q(2)j + q(3)k + E(q(4) + q(5)i + 0j + 0k) instead of 0 + q(0)i + q(1)j + q(2)k + E(0 + q(3)i + q(4)j + q(5)k).

To Reproduce

Code

#include <iostream>
#include <Eigen/Dense>
#include <dqrobotics/DQ.h>
#include <iostream>

using namespace DQ_robotics;

int main()
{
    Eigen::VectorXd force(6);
    force << 1, 2, 3, 4, 5, 6;
    std::cout << DQ(force) << std::endl;
   return 0;
}

Output

1 2i 3j 4k +E( 5 6i 0j 0k )

Expected behavior

Expected output

0 1i 2j 3k +E( 0 4i 5j 6k )

Environment:

OS: Ubuntu16.04
dqrobotics version: 0.1.0

Additional context

It works fine in MATLAB version.

dqrobotics / cpp

[BUG] The constructor of DQ does not work for pure dual quaternions #24