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: CO_fzcglscf.m
    path of file: ./repos/hctsa/Operations
    
    the code of the file until where you have to start completion: function out = CO_fzcglscf(y,alpha,beta,maxtau)
% CO_fzcglscf   The first zero-crossing of the generalized self-correlation function
%
% Returns the first zero-crossing of the generalized self-correlation function
% introduced in Duarte Queiros and Moyano in Physica A, Vol. 383, pp. 10--15
% (2007) in the paper "Yet on statistical properties of traded volume:
% Correlation and mutual information at different value magnitudes"
% Uses CO_glscf to calculate the generalized self-correlations.
% Keeps calculating until the function finds a minimum, and returns this lag.
%
%---INPUTS:
% y, the input time series.
% alpha, the parameter alpha.
% beta, the parameter beta.
% maxtau [opt], a maximum time delay to search up to (default is the time-series
%                length).

% ------------------------------------------------------------------------------
% Copyright (C) 2020, Ben D. Fulcher <ben.d.fulcher@gmail.com>,
% <http://www.benfulcher.com>
%

    
function out = CO_fzcglscf(y,alpha,beta,maxtau)
% CO_fzcglscf   The first zero-crossing of the generalized self-correlation function
%
% Returns the first zero-crossing of the generalized self-correlation function
% introduced in Duarte Queiros and Moyano in Physica A, Vol. 383, pp. 10--15
% (2007) in the paper "Yet on statistical properties of traded volume:
% Correlation and mutual information at different value magnitudes"
% Uses CO_glscf to calculate the generalized self-correlations.
% Keeps calculating until the function finds a minimum, and returns this lag.
%
%---INPUTS:
% y, the input time series.
% alpha, the parameter alpha.
% beta, the parameter beta.
% maxtau [opt], a maximum time delay to search up to (default is the time-series
%                length).

% ------------------------------------------------------------------------------
% Copyright (C) 2020, Ben D. Fulcher <ben.d.fulcher@gmail.com>,
% <http://www.benfulcher.com>
%
% If you use this code for your research, please cite the following two papers:
%
% (1) B.D. Fulcher and N.S. Jones, "hctsa: A Computational Framework for Automated
% Time-Series Phenotyping Using Massive Feature Extraction, Cell Systems 5: 527 (2017).
% DOI: 10.1016/j.cels.2017.10.001
%
% (2) B.D. Fulcher, M.A. Little, N.S. Jones, "Highly comparative time-series
% analysis: the empirical structure of time series and their methods",
% J. Roy. Soc. Interface 10(83) 20130048 (2013).
% DOI: 10.1098/rsif.2013.0048
%
% This function is free software: you can redistribute it and/or modify it under
% the terms of the GNU General Public License as published by the Free Software
% Foundation, either version 3 of the License, or (at your option) any later
% version.
%
% This program is distributed in the hope that it will be useful, but WITHOUT
% ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
% FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
% details.
%
% You should have received a copy of the GNU General Public License along with
% this program. If not, see <http://www.gnu.org/licenses/>.
% ------------------------------------------------------------------------------

N = length(y); % the length of the time series

if nargin < 4 || isempty(maxtau)
    maxtau = N;
    % maxtau = 400; % searches up to this maximum time lag
    % maxtau = min(maxtau,N); % make sure no longer than the time series itself
end