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: Griewank.m
    path of file: ./repos/Algorithms_MathModels/MATLAB智能算法30个案例分析/chapter17 基于PSO工具箱的函数寻优算法/testfunctions
    
    the code of the file until where you have to start completion: % Griewank.m
% Griewank function
% described by Clerc in ...
% http://clerc.maurice.free.fr/pso/Semi-continuous_challenge/Semi-continuous_challenge.htm
%
% used to test optimization/global minimization problems 
% in Clerc's "Semi-continuous challenge"
%
% f(x) = sum((x
    
function
% described by Clerc in ...
% http://clerc.maurice.free.fr/pso/Semi-continuous_challenge/Semi-continuous_challenge.htm
%
% used to test optimization/global minimization problems 
% in Clerc's "Semi-continuous challenge"
%
% f(x) = sum((x-100).^2,2)./4000 - ...
%        prod(cos((x-100)./(sqrt(repmat([1:N],length(x(:,1),1)))),2) ...
%        +1
% 
% x = N element row vector containing [x0, x1, ..., xN]
% each row is processed independ