function d=dist(x,y)
// calcule les distances 2 a 2 
// x est une matrice mx * n 
// y est une matrice my * n 
// renvoit une matrice d = dist(x(i,:),y(j,:)) 
  [mx,n]=size(x)
  [my,n]=size(y)
  d = 0*ones(mx,my) 
  for i=1:mx
    d1= sum( abs(y - ones(my,1)* x(i,:)),'c')
    d(i,:) = d1'
  end
endfunction 

x=int(2*rand(10,2))
d=dist(x,x)

function steps=stepeval(x,y)
// x and y are row vectors 
// d is the distance between x,y 
// try to compute a suite of transformations 
// leading from x to y 
  [mx,n]=size(x)
  Inds = find( x<>y) 
  nsteps= size(Inds,'*')-1
  steps = ones(nsteps,n)
  steps(1,:)=x(:)';
  steps(1,Inds(1))=bool2s(~steps(1,Inds(1)));
  for i = 2:nsteps
    steps(i,:)= steps(i-1,:);
    steps(i,Inds(i))=bool2s(~steps(i-1,Inds(i)));
  end
endfunction