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: addedMassSurge.m
    path of file: ./repos/MSS/GNC
    
    the code of the file until where you have to start completion: function [A11,ratio] = addedMassSurge(m,L,rho)
% A11 = addedMassSurge(m,L,rho) approximates the added mass in surge by
% the formula of Söding (1982):
%
%   A11 = -Xudot = 2.7 * rho * nabla^(5/3) / L^2
%
% Output:  
%   A11: added mass in surge due to a linear acceleration in surge (kg)
%   ratio: optional output for computation of the mass ratio A11/m,
%          typical values are ratios < 0.20.
%
% Inputs:   
%   m: ship/vehicle mass (kg)
%   L: ship/vehicle length (m)
%   rho: density of water, default value 1025 (kg/m3)
%
% Examples:
%   A11 = addedMassSurge(m,L)         - use default rho = 1025 (kg/m3)
%   A11 = addedMassSurge(m,L,rho)
%   [A11,ratio] = addedMassSurge(m,L,rho)
%
% Reference: H. Söding (1982). Prediction of Ship Steering Capabilities. 

    
function [A11,ratio] = addedMassSurge(m,L,rho)
% A11 = addedMassSurge(m,L,rho) approximates the added mass in surge by
% the formula of Söding (1982):
%
%   A11 = -Xudot = 2.7 * rho * nabla^(5/3) / L^2
%
% Output:  
%   A11: added mass in surge due to a linear acceleration in surge (kg)
%   ratio: optional output for computation of the mass ratio A11/m,
%          typical values are ratios < 0.20.
%
% Inputs:   
%   m: ship/vehicle mass (kg)
%   L: ship/vehicle length (m)
%   rho: density of water, default value 1025 (kg/m3)
%
% Examples:
%   A11 = addedMassSurge(m,L)         - use default rho = 1025 (kg/m3)
%   A11 = addedMassSurge(m,L,rho)
%   [A11,ratio] = addedMassSurge(m,L,rho)
%
% Reference: H. Söding (1982). Prediction of Ship Steering Capabilities. 
%   Schiffstechnik, 3-29.
%  
% Author:    Thor I. Fossen
% Date:      17 Dec 2021
% Revisions: 

if (nargin == 2)
    rho = 1025;                         % default density of water (kg/m3)
end