tensorflow embedding_lookup & embedding_lookup_sparse用法

import tensorflow as tf
import numpy as np

def test_embedding_lookup():
    a = np.arange(8).reshape(2,4)
    b = np.arange(8,12).reshape(1,4)
    c = np.arange(12, 20).reshape(2,4)
    print('a = ', a)
    print('b = ', b)
    print('c = ', c)

    a = tf.Variable(a)
    b = tf.Variable(b)
    c = tf.Variable(c)

    t = tf.nn.embedding_lookup([a,b,c], ids=[0,1,2,3])

    init = tf.global_variables_initializer()
    sess = tf.Session()
    sess.run(init)
    r = sess.run(t)
    print('r = ', r)

test_embedding_lookup()
import tensorflow a