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: initialize.m
    path of file: ./repos/Isogeometric-Analysis/models/phase_field_new/1d_brittle_fracture_alternating_lmm_version2
    
    the code of the file until where you have to start completion: %--------------------------------------------------------------------------
%  Author: Isaac J. Lee (ijlee2@ices.utexas.edu)
%  
%  
%  Summary:
%  
%  This routine initial
    
function u = function_u_exact(x, u_L, epsilon, order)
    switch order
        case 2
            if (x < -epsilon)
                u = 0;
            elseif (x < epsilon)
                u = u_L/(2*epsilon) * (x + epsilon);
            else
                u = u_L;
            end