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: upwindMean1D.m
    path of file: ./repos/FVTool/Utilities
    
    the code of the file until where you have to start completion: function phiFaceAverage = upwindMean1D(phi, u)
% This function gets the value of the field variable phi defined
% over the MeshStructure and calculates the upwind average on
% the cell faces, based on the direction of the velocity vector for a uniform mesh.
%
% SYNOPSIS:
%   phiFaceAverage = upwindMean1D(phi, u)
%
% PARAMETERS:
%
%
% RETURNS:
%
%
% EXAMPLE:
%
% SEE ALSO:
%


    
function phiFaceAverage = upwindMean1D(phi, u)
% This function gets the value of the field variable phi defined
% over the MeshStructure and calculates the upwind average on
% the cell faces, based on the direction of the velocity vector for a uniform mesh.
%
% SYNOPSIS:
%   phiFaceAverage = upwindMean1D(phi, u)
%
% PARAMETERS:
%
%
% RETURNS:
%
%
% EXAMPLE:
%
% SEE ALSO:
%

% Written by Ali A. Eftekhari
% See the license file

% extract the velocity data
% note: size(ux) = [1:m+1, 1:n] and size(uy) = [1:m, 1:n+1]
ux = u.xvalue;

% check the size of the variable and the mesh dimension
Nx = phi.domain.dims(1);

% assign to a temp variable for boundary corrections
phi_tmp = phi.value;

% correct the value of phi at the boundary (calculation trick)
% assign the value of the left boundary to the left ghost cell
phi_tmp(1) = (phi.value(1)+phi.value(2))/2;
% assign the value of the right boundary to the right ghost cell
phi_tmp(end