--- /dev/null
+## Copyright (C) 2006 Muthiah Annamalai <muthiah.annamalai@uta.edu>
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{dist},@var{L}] =} editdistance (@var{string1}, @var{string2}, @var{weights})
+## Compute the Levenshtein edit distance between the strings @var{string1} and
+## @var{string2}. This operation is symmetrical.
+##
+## The optional argument @var{weights} specifies weights for the
+## deletion, matched, and insertion operations; by default it is set to
+## +1, 0, +1 respectively, so that a least editdistance means a
+## closer match between the two strings. This function implements
+## the Levenshtein edit distance as presented in Wikipedia article,
+## accessed Nov 2006. Also the levenshtein edit distance of a string
+## with an empty string is defined to be its length.
+##
+## The default return value is @var{dist} the edit distance, and
+## the other return value @var{L} is the distance matrix.
+##
+## @example
+## @group
+## editdistance('marry','marie')
+## ##returns value +2 for the distance.
+## @end group
+## @end example
+##
+## @end deftypefn
+
+function [dist, L] = editdistance (str1, str2, weights)
+ if(nargin < 2 || (nargin == 3 && length(weights) < 3) )
+ print_usage();
+ end
+
+ L1=length(str1)+1;
+ L2=length(str2)+1;
+ L=zeros(L1,L2);
+
+ if(nargin < 3)
+ g=+1;%insertion
+ m=+0;%match
+ d=+1;%deletion
+ else
+ g=weights(1);
+ m=weights(2);
+ d=weights(3);
+ end
+
+ L(:,1)=[0:L1-1]'*g;
+ L(1,:)=[0:L2-1]*g;
+
+ m4=0;
+ for idx=2:L1;
+ for idy=2:L2
+ if(str1(idx-1)==str2(idy-1))
+ score=m;
+ else
+ score=d;
+ end
+ m1=L(idx-1,idy-1) + score;
+ m2=L(idx-1,idy) + g;
+ m3=L(idx,idy-1) + g;
+ L(idx,idy)=min(m1,min(m2,m3));
+ end
+ end
+
+ dist=L(L1,L2);
+endfunction