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: MD_polvar.m
    path of file: ./repos/hctsa/Operations
    
    the code of the file until where you have to start completion: function p = MD_polvar(x, d, D)
% MD_polvar     The POLVARd measure of a time series.
%
% Measures the probability of obtaining a sequence of consecutive ones or zeros.
%
% The first mention may be in Wessel et al., PRE (2000), called Plvar
% cf. "Short-term forecasting of life-threatening cardiac arrhythmias based on
% symbolic dynamics and finite-time growth rates",
%       N. Wessel et al., Phys. Rev. E 61(1) 733 (2000)
%
% Although the original measure used raw thresholds, d, on RR interval sequences
% (measured in milliseconds), this code can be applied to general z-scored time
% series. So now d is not the time difference in milliseconds, but in units of
% std.
%
% The measure was originally applied to sequences of RR intervals and this code
% is heavily derived from that provided by Max A. Little, January 2009.
% cf. http://www.maxlittle.net/
%
%---INPUTS:
% x, the input time series
% d, the symbolic coding (amplitude) difference
% D, the word length (classically words of length 6)
%
%---OUPUT:
% p - probability of obtaining a sequence of consecutive ones/zeros

% ------------------------------------------------------------------------------
% Copyright (C) 2016, Max A. Little, <max.a.little@gmail.com>,
% <http://www.maxlittle.net/> and 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

    
function p = MD_polvar(x, d, D)
% MD_polvar     The POLVARd measure of a time series.
%
% Measures the probability of obtaining a sequence of consecutive ones or zeros.
%
% The first mention may be in Wessel et al., PRE (2000), called Plvar
% cf. "Short-term forecasting of life-threatening cardiac arrhythmias based on
% symbolic dynamics and finite-time growth rates",
%       N. Wessel et al., Phys. Rev. E 61(1) 733 (2000)
%
% Although the original measure used raw thresholds, d, on RR interval sequences
% (measured in milliseconds), this code can be applied to general z-scored time
% series. So now d is not the time difference in milliseconds, but in units of
% std.
%
% The measure was originally applied to sequences of RR intervals and this code
% is heavily derived from that provided by Max A. Little, January 2009.
% cf. http://www.maxlittle.net/
%
%---INPUTS:
% x, the input time series
% d, the symbolic coding (amplitude) difference
% D, the word length (classically words of length 6)
%
%---OUPUT:
% p - probability of obtaining a sequence of consecutive ones/zeros

% ------------------------------------------------------------------------------
% Copyright (C) 2016, Max A. Little, <max.a.little@gmail.com>,
% <http://www.maxlittle.net/> and 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/>.
% ------------------------------------------------------------------------------

% ------------------------------------------------------------------------------
% Check Inputs:
% ------------------------------------------------------------------------------

% coding time difference, d
if nargin < 2 || isempty(d)
    d = 1;
end