meshcentroid

 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)

0001 function centroid=meshcentroid(v,f)
0002 %
0003 % centroid=meshcentroid(v,f)
0004 %
0005 % compute the centroids of a mesh defined by nodes and elements
0006 % (surface or tetrahedra) in R^n space
0007 %
0008 % author: Qianqian Fang, <q.fang at neu.edu>
0009 %
0010 % input:
0011 %      v: surface node list, dimension (nn,3)
0012 %      f: surface face element list, dimension (be,3)
0013 %
0014 % output:
0015 %      centroid: centroid positions, one row for each element
0016 %
0017 % -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
0018 %
0019 
0020 if(~iscell(f))
0021     ec=reshape(v(f(:,1:size(f,2))',:)', [size(v,2) size(f,2) size(f,1)]);
0022     centroid=squeeze(mean(ec,2))';
0023 else
0024     len=length(f);
0025     centroid=zeros(len,size(v,2));
0026     try
0027         for i=1:len
0028             fc=f{i};
0029             if(~isempty(fc)) % need to set centroid to NaN if fc is empty?
0030                 vlist=fc{1};
0031                 centroid(i,:)=mean(v(vlist(find(~isnan(vlist))),:));
0032             end
0033         end
0034     catch
0035         error('malformed face cell array');
0036     end
0037 end
0038