ekernels.py 文件源码

def exKxz_pairwise(self, Z, Xmu, Xcov):
        with tf.control_dependencies([
            tf.assert_equal(tf.shape(Xmu)[1], tf.constant(self.input_dim, settings.tf_int),
                            message="Currently cannot handle slicing in exKxz."),
            tf.assert_equal(tf.shape(Xmu), tf.shape(Xcov)[1:3], name="assert_Xmu_Xcov_shape")
        ]):
            Xmu = tf.identity(Xmu)

        N = tf.shape(Xmu)[0] - 1
        Xmum = Xmu[:-1, :]
        Xmup = Xmu[1:, :]
        op = tf.expand_dims(Xmum, 2) * tf.expand_dims(Xmup, 1) + Xcov[1, :-1, :, :]  # NxDxD
        return self.variance * tf.matmul(tf.tile(tf.expand_dims(Z, 0), (N, 1, 1)), op)