nbof.py 文件源码

def symbolic_distance_matrix(A, B):
    """
    Defines the symbolic matrix that contains the distances between the vectors of A and B
    :param A:
    :param B:
    :return:
    """
    aa = T.sum(A * A, axis=1)
    bb = T.sum(B * B, axis=1)
    AB = T.dot(A, T.transpose(B))

    AA = T.transpose(T.tile(aa, (bb.shape[0], 1)))
    BB = T.tile(bb, (aa.shape[0], 1))

    D = AA + BB - 2 * AB
    D = T.maximum(D, 0)
    D = T.sqrt(D)
    return D