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: f_pinknoise.m
    path of file: ./repos/erplab/functions
    
    the code of the file until where you have to start completion: % Author: Guanghui Zhang & Steve J. Luck & Andrew Stewart
% Center for Mind and Brain
% University of California, Davis,
% Davis, CA
% Mar. 2023



%%Thanks for Hristo Zhivomirov function, Mar 2023 Davis CA USA
%%https://github.com/cortex-lab/MATLAB-tools/blob/master/pinknoise.m
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   Pink Noise Generation with MATLAB Implementation   %
%                                                      %
% Author: M.Sc. Eng. Hristo 
    
function y = f_pinknoise(N)

% function: y = pinknoise(N) 
% N - number of samples to be returned in row vector
% y - row vector of pink (flicker) noise samples

% The function generates a sequence of pink (flicker) noise samples. 
% Pink noise has equal energy in all octaves (or similar log bundles) of frequency.
% In terms of power at a constant bandwidth, pink noise falls off at 3 dB per octave. 

% define the length of the vector
% ensure that the M is even
if rem(N,2)
    M = N+1;
else
    M = N;
end