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: meshcentroid.m
    path of file: ./repos/iso2mesh
    
    the code of the file until where you have to start completion: function centroid=meshcentroid(v,f)
%
% centroid=meshcentroid(v,f)
% 
% compute the centroids of a mesh defined by nodes and elements
% (surface or tetrahedra) in R^n space
%
% author: Qianqian Fang, <q.fang at neu.edu>
%

    
function centroid=meshcentroid(v,f)
%
% centroid=meshcentroid(v,f)
% 
% compute the centroids of a mesh defined by nodes and elements
% (surface or tetrahedra) in R^n space
%
% author: Qianqian Fang, <q.fang at neu.edu>
%
% input:
%      v: surface node list, dimension (nn,3)
%      f: surface face element list, dimension (be,3)
%
% output:
%      centroid: centroid positions, one row for each element
%
% -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
%

if(~iscell(f))
    ec=reshape(v(f(:,1:size(f,2))',:)', [size(v,2) size(f,2) size(f,1)]);
    centroid=squeeze(mean(ec,2))';
else
    len=length(f);
    centroid=zeros(len,size(v,2));
    try
        for i=1:len
            fc=f{i};
            if(~isempty(fc)) % need to set centroid to NaN if fc is empty?
                vlist=fc{1};
                centroid(i,:)=mean(v(vlist(find(~isnan(vlist))),:));
            end