function p = lorentz(x,y)
%LORENTZ  Calculates the Lorentz inner product of the two
%         4 by 1 vectors x and y

%Kai Borre 04-22-95
%Copyright (c) by Kai Borre
%$Revision: 1.0 $ $Date: 1997/09/26  $

% M = diag([1 1 1 -1]);
% p = x'*M*y;

p = x(1)*y(1) + x(2)*y(2) + x(3)*y(3) - x(4)*y(4);
%%%%%%%%%% end lorentz.m %%%%%%%%%%%%%%%