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: surfinterior.m
    path of file: ./repos/iso2mesh
    
    the code of the file until where you have to start completion: function [pt,p0,v0,t,idx]=surfinterior(node,face)
%
% [pt,p0,v0,t,idx]=surfinterior(node,face)
%
% identify a point that is enclosed by the (closed) surface
%
% author: Qianqian Fang, <q.fang at neu.edu>
%
% input:
%   node: a list of node coordinates (nn x 3)
%   face: a surface mesh triangle list (ne x 3)
%
% output:
%   pt: the interior point coordinates [x y z]
%   p0: ray origin used to determine the interior point
%   v0: the vector used to determine the interior point
%   t : ray-tracing intersection distances (with signs) from p0. the
%       intersection coordinates can be expressed as p0+t(i)*v0
%   idx: index to the face elements that intersect with the ray, order
%       match that of t
%
% -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
%

pt=[];
len=size(face,1);
for i=1:len

    
function [pt,p0,v0,t,idx]=surfinterior(node,face)
%
% [pt,p0,v0,t,idx]=surfinterior(node,face)
%
% identify a point that is enclosed by the (closed) surface
%
% author: Qianqian Fang, <q.fang at neu.edu>
%
% input:
%   node: a list of node coordinates (nn x 3)
%   face: a surface mesh triangle list (ne x 3)
%
% output:
%   pt: the interior point coordinates [x y z]
%   p0: ray origin used to determine the interior point
%   v0: the vector used to determine the interior point
%   t : ray-tracing intersection distances (with signs) from p0. the
%       intersection coordinates can be expressed as p0+t(i)*v0
%   idx: index to the face elements that intersect with the ray, order
%       match that of t
%
% -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
%

pt=[];
len=size(face,1);
for i=1:len
   p0=mean(node(face(i,1:3),:));
   plane=surfplane(node,face(i,:));
   v0=plane(1:3);

   [t,u,v]=raytrace(p0,v0,node,face(:,1:3));

   idx=find(u>=0 & v>=0 & u+v<=1.0 & ~isinf(t));
   [ts, uidx]=unique(sort(t(idx)));
   if(~isempty(ts) && mod(length(ts),2)==0)
       ts=reshape(ts,[2 length(ts)/2]);
       tdiff=ts(2,:)-ts(1,:);
       [maxv,maxi]=max(tdiff);
       pt=p0+v0*(ts(1,maxi)+ts(2,maxi))*0.5;
       idx=idx(uidx);
       t=t(idx);
       break;
   end