\[ M= \left(\begin{array}{ccc} 1 & \tan{(\theta_{xy/2})} & \tan{(\theta_{xz/2})}\\ \tan{(\theta_{xy/2})} & 1 & \tan{(\theta_{yz/2})}\\ \tan{(\theta_{xz/2})} & \tan{(\theta_{yz/2})} & 1 \end{array} \right) \]