function ker = string_kernel_brute(s,t)
SS1 = all_subseq(s);
SS2 = all_subseq(t);
CAP = intersect(SS1,SS2)

ker = length(CAP);

return



function S = all_subseq(s)
n = length(s);
POWSET = list_all_ind(repmat([2],[n 1]))-1;
S = repmat({s},size(POWSET,1),1);
for j = 1:length(S)
  S{j} = s(find(POWSET(j,:)));
end
S = unique(S);
return



function ker = string_kernel_brute_old(s,t)

SS1 = all_subseq(s);
SS2 = all_subseq(t);

ASS = union(SS1,SS2);
%ISS = intersect(SS1,SS2)

N1 = str_stats(ASS,SS1);
N2 = str_stats(ASS,SS2);

N1 = ~~N1;
N2 = ~~N2;

ker = sum(N1.*N2);

%ker = length(intersect(SS1,SS2));

return


function S = all_subseq_old(s)
S = {};
for i=1:length(s)
  x = s(i);
  S1 = S;
  %S1{end+1} = '';
  S1 = [{''} S1];
  for j=1:length(S1)
    u = S1{j};
    ux = [u x];
    %if isempty(strmatch(ux,S,'exact'))
      S{end+1} = ux;
    %end
  end
end
return


function N = str_stats(U,V)
%function [U,N] = str_stats(V)
%U = unique(V);
N = zeros(length(U),1);
for j=1:length(U)
  N(j) = length(strmatch(U{j},V,'exact'));
end
return