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: EN_Randomize.m
    path of file: ./repos/hctsa/Operations
    
    the code of the file until where you have to start completion: function out = EN_Randomize(y,randomizeHow,randomSeed)
% EN_Randomize  How time-series properties change with increasing randomization.
%
% Progressively randomizes the input time series according to a specified
% randomizatio
    
function [c,gof] = f_fix_exp(r,dataVector,startPoint,addOffset)
    % Fits an exponential to the data vector across data points r

    s = fitoptions('Method','NonlinearLeastSquares','StartPoint',startPoint);
    if addOffset
        f = fittype('a*exp(b*x)+c','options',s);
        f_x = @(c,x) c.a*exp(c.b*x)+c.c;
    else
        f = fittype('a*exp(b*x)','options',s);
        f_x = @(c,x) c.a*exp(c.b*x);
    end