Pure abstract class implementing constraint application on multiple tracks (back to back, collinearity etc.) To be used by KinematicConstraindeVertexFitter only Class caches the information about calculation of of constraint equation derivatives and values at given linearization point. Point should be of 7*n+3 dimensions Where n - number of particles. 7 - parametrization for particles is (x,y,z,p_x,p_y,p_z,m), for vertex (x_v,y_v,z_v) Fitter usually takes current parameters as the first step point and the change it to the result of the first iteration.
Kirill Prokofiev, October 2003
New version: make use of SMatrix: optimize filling of matrices Vincenzo Innocente, October 2010
Definition at line 27 of file MultiTrackKinematicConstraintT.h.