Kronecker tensor product.

  KRON(X,Y) is the Kronecker tensor product of X and Y.

  The result is a large matrix formed by taking all possible

  products between the elements of X and those of Y.   For

  example, if X is 2 by 3, then KRON(X,Y) is



     [ X(1,1)*Y  X(1,2)*Y  X(1,3)*Y

       X(2,1)*Y  X(2,2)*Y  X(2,3)*Y ]