You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: nrotor_dynamics.m
    path of file: ./repos/robotics-toolbox-matlab/simulink
    
    the code of the file until where you have to start completion: 
function [sys,x0,str,ts] = nrotor_dynamics(t,x,u,flag, vehicle, x0, groundflag)
    % Flyer2dynamics lovingly coded by Paul Pounds, first coded 12/4/04
    % A simulation of idealised X-4 Flyer II flight dynamics.
    % version 2.0 2005 modified to be compatible with latest version of Matlab
    % version 3.0 2006 fixed rotation matrix problem
    % version 4.0 4/2/10, fixed rotor flapping rotation matrix bug, mirroring
    % version 5.0 8/8/11, simplified and restructured
   % version 6.0 25/10/13, fixed rotation matrix/inverse wronskian definitions, flapping cross-product bug
    

    
function of state vector
    %   z      Position                         3x1   (x,y,z)
    %   v      Velocity                         3x1   (xd,yd,zd)
    %   n      Attitude                         3x1   (Y,P,R)
    %   o      Angular velocity                 3x1   (Yd,Pd,Rd)
    
    n = x(4:6);   % RPY angles
    phi = n(1);    % yaw
    the = n(2);    % pitch
    psi = n(3);    % roll
    
    
    % rotz(phi)*roty(the)*rotx(psi)
    R = [cos(the)*cos(phi) sin(psi)*sin(the)*cos(phi)-cos(psi)*sin(phi) cos(psi)*sin(the)*cos(phi)+sin(psi)*sin(phi);   %BBF > Inertial rotation matrix
         cos(the)*sin(phi) sin(psi)*sin(the)*sin(phi)+cos(psi)*cos(phi) cos(psi)*sin(the)*sin(phi)-sin(psi)*cos(phi);
         -sin(the)         sin(psi)*cos(the)                            cos(psi)*cos(the)];
    
    iW = [0        sin(psi)          cos(psi);             %inverted Wronskian
          0        cos(psi)*cos(the) -sin(psi)*cos(the);
          cos(the) sin(psi)*sin(the) cos(psi)*sin(the)] / cos(the);
    
    % return velocity in the body frame
    sys = [ x(1:6);
            inv(R)*x(7:9);   % translational velocity mapped to body frame
            iW*x(10:12)];    % RPY rates mapped to body frame
    %sys = [x(1:6); iW*x(7:9);  iW*x(10:12)];
    %sys = x;
end