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: container.m
    path of file: ./repos/MSS/VESSELS
    
    the code of the file until where you have to start completion: function [xdot,U] = container(x,ui)
% [xdot,U] = container(x,ui) returns the speed U in m/s (optionally) and the 
% time derivative of the state vector: x = [ u v r x y psi p phi delta n ]'
% for a container ship L = 175 m, where
%
% u     = surge velocity          (m/s)
% v     = sway velocity           (m/s)
% r     = yaw velocity            (rad/s)
% x     = position in x-direction (m)
% y     = position in y-direction (m)
% psi   = yaw angle               (rad)
% p     = roll velocity           (rad/s)
% phi   = roll angle              (rad)
% delta = actual rudder angle     (rad)
% n     = actual shaft velocity   (rpm)

    
function [xdot,U] = container(x,ui)
% [xdot,U] = container(x,ui) returns the speed U in m/s (optionally) and the 
% time derivative of the state vector: x = [ u v r x y psi p phi delta n ]'
% for a container ship L = 175 m, where
%
% u     = surge velocity          (m/s)
% v     = sway velocity           (m/s)
% r     = yaw velocity            (rad/s)
% x     = position in x-direction (m)
% y     = position in y-direction (m)
% psi   = yaw angle               (rad)
% p     = roll velocity           (rad/s)
% phi   = roll angle              (rad)
% delta = actual rudder angle     (rad)
% n     = actual shaft velocity   (rpm)
%
% The input vector is:
%
% ui      = [ delta_c n_c ]'  where
%
% delta_c = commanded rudder angle (rad)
% n_c     = commanded shaft speed (rpm)  
%
% Reference:  Son og Nomoto (1982). On the Coupled Motion of Steering and 
%             Rolling of a High Speed Container Ship, Naval Architect of 
%             Ocean Engineering 20:73-83. FromJ.S.N.A., Japan, Vol. 150, 1981.
% 
% Author:    Trygve Lauvdal
% Date:      12 May 1994
% Revisions: 18 July 2001 added output U, changed order of x-vector
%            20 July 2001 changed my = 0.000238 to my = 0.007049
%            27 July 2022 corrected the equation for up = u * (...

if (length(x) ~= 10),error('x-vector must have dimension 10 !');end