> If I'm the author of this comment in the sources (I am, probably), > "close to identity" means close to null rotation. In other words the > corresponding rotation matrix is very close to identity matrix. > So, let M be a rotation matrix defining a rotation of 10^-8 degrees. > Theoretically, M*M^(-1)=Id. > Now, do the same numerically with quaternions : let q be the quaternion > representing the same rotation as matrix M, and compute q*q.conjugate(). > It seems, sometimes in Eigen, the result will be NaN. > As a workaround, I set angle=0 when angle=NaN.
Bruno, could you post that issue to eigen's forums http://eigen.tuxfamily.org/index.php?title=Main_Page#Get_support? They are very responsive as far as my experience goes and will give us proper mathematical explanation about the cause. v _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp
