def _distance_matrix(self, a, b):
def sq(x): return (x * x)<EOL>matrix = sq(a[:, <NUM_LIT:0>][:, None] - b[:, <NUM_LIT:0>][None, :])<EOL>for x, y in zip(a.T[<NUM_LIT:1>:], b.T[<NUM_LIT:1>:]):<EOL><INDENT>matrix += sq(x[:, None] - y[None, :])<EOL><DEDENT>return matrix<EOL>
Pairwise distance between each point in `a` and each point in `b`