我收到此错误
＆＃39; ValueError：Tensor Tensor（＆＃34;占位符：0＆＃34;，shape =（1,1），dtype = int32） 不是此图表的元素。＆＃39;
没有with tf.Graph(). as_default():，代码运行得很好。但是，我需要多次致电M.sample(...)，每次session.close()之后内存都不会被释放。可能存在内存泄漏，但不确定它在哪里。
我想恢复预先训练好的神经网络，将其设置为默认图形，并在默认图形上多次测试（如10000），而不是每次都更大。
代码是：
def SessionOpener(save):
grph = tf.get_default_graph()
sess = tf.Session(graph=grph)
ckpt = tf.train.get_checkpoint_state(save)
saver = tf.train.import_meta_graph('./predictor/save/model.ckpt.meta')
if ckpt and ckpt.model_checkpoint_path:
saver.restore(sess, ckpt.model_checkpoint_path)
tf.global_variables_initializer().run(session=sess)
return sess
def LoadPredictor(save):
with open(os.path.join(save, 'config.pkl'), 'rb') as f:
saved_args = cPickle.load(f)
with open(os.path.join(save, 'words_vocab.pkl'), 'rb') as f:
words, vocab = cPickle.load(f)
model = Model(saved_args, True)
return model, words, vocab
if __name__ == '__main__':
Save = './save'
M, W, V = LoadPredictor(Save)
Sess = SessionOpener(Save)
word = M.sample(Sess, W, V, 1, str(123), 2, 1, 4)
Sess.close()
模型是：
class Model():
def __init__(self, args, infer=False):
with tf.Graph().as_default():
self.args = args
if infer:
args.batch_size = 1
args.seq_length = 1
if args.model == 'rnn':
cell_fn = rnn.BasicRNNCell
elif args.model == 'gru':
cell_fn = rnn.GRUCell
elif args.model == 'lstm':
cell_fn = rnn.BasicLSTMCell
else:
raise Exception("model type not supported: {}".format(args.model))
cells = []
for _ in range(args.num_layers):
cell = cell_fn(args.rnn_size)
cells.append(cell)
self.cell = cell = rnn.MultiRNNCell(cells)
self.input_data = tf.placeholder(tf.int32, [args.batch_size, args.seq_length])
self.targets = tf.placeholder(tf.int32, [args.batch_size, args.seq_length])
self.initial_state = cell.zero_state(args.batch_size, tf.float32)
self.batch_pointer = tf.Variable(0, name="batch_pointer", trainable=False, dtype=tf.int32)
self.inc_batch_pointer_op = tf.assign(self.batch_pointer, self.batch_pointer + 1)
self.epoch_pointer = tf.Variable(0, name="epoch_pointer", trainable=False)
self.batch_time = tf.Variable(0.0, name="batch_time", trainable=False)
tf.summary.scalar("time_batch", self.batch_time)
def variable_summaries(var):
"""Attach a lot of summaries to a Tensor (for TensorBoard visualization)."""
with tf.name_scope('summaries'):
mean = tf.reduce_mean(var)
tf.summary.scalar('mean', mean)
tf.summary.scalar('max', tf.reduce_max(var))
tf.summary.scalar('min', tf.reduce_min(var))
with tf.variable_scope('rnnlm'):
softmax_w = tf.get_variable("softmax_w", [args.rnn_size, args.vocab_size])
variable_summaries(softmax_w)
softmax_b = tf.get_variable("softmax_b", [args.vocab_size])
variable_summaries(softmax_b)
with tf.device("/cpu:0"):
embedding = tf.get_variable("embedding", [args.vocab_size, args.rnn_size])
inputs = tf.split(tf.nn.embedding_lookup(embedding, self.input_data), args.seq_length, 1)
inputs = [tf.squeeze(input_, [1]) for input_ in inputs]
def loop(prev, _):
prev = tf.matmul(prev, softmax_w) + softmax_b
prev_symbol = tf.stop_gradient(tf.argmax(prev, 1))
return tf.nn.embedding_lookup(embedding, prev_symbol)
outputs, last_state = legacy_seq2seq.rnn_decoder(inputs, self.initial_state, cell, loop_function=loop if infer else None, scope='rnnlm')
output = tf.reshape(tf.concat(outputs, 1), [-1, args.rnn_size])
self.logits = tf.matmul(output, softmax_w) + softmax_b
self.probs = tf.nn.softmax(self.logits)
loss = legacy_seq2seq.sequence_loss_by_example([self.logits],
[tf.reshape(self.targets, [-1])],
[tf.ones([args.batch_size * args.seq_length])],
args.vocab_size)
self.cost = tf.reduce_sum(loss) / args.batch_size / args.seq_length
tf.summary.scalar("cost", self.cost)
self.final_state = last_state
self.lr = tf.Variable(0.0, trainable=False)
tvars = tf.trainable_variables()
grads, _ = tf.clip_by_global_norm(tf.gradients(self.cost, tvars),
args.grad_clip)
optimizer = tf.train.AdamOptimizer(self.lr)
self.train_op = optimizer.apply_gradients(zip(grads, tvars))
def sample(self, sess, words, vocab, num=200, prime='first all', sampling_type=1, pick=0, width=4):
def weighted_pick(weights):
t = np.cumsum(weights)
s = np.sum(weights)
return(int(np.searchsorted(t, np.random.rand(1)*s)))
ret = ''
if pick == 1:
state = sess.run(self.cell.zero_state(1, tf.float32))
if not len(prime) or prime == ' ':
prime = random.choice(list(vocab.keys()))
for word in prime.split()[:-1]:
x = np.zeros((1, 1))
x[0, 0] = vocab.get(word,0)
feed = {self.input_data: x, self.initial_state:state}
[state] = sess.run([self.final_state], feed)
ret = prime
word = prime.split()[-1]
for n in range(num):
x = np.zeros((1, 1))
x[0, 0] = vocab.get(word, 0)
feed = {self.input_data: x, self.initial_state:state}
[probs, state] = sess.run([self.probs, self.final_state], feed)
p = probs[0]
if sampling_type == 0:
sample = np.argmax(p)
elif sampling_type == 2:
if word == '\n':
sample = weighted_pick(p)
else:
sample = np.argmax(p)
else: # sampling_type == 1 default:
sample = weighted_pick(p)
ret = words[sample]
return ret
，输出为：
Traceback (most recent call last):
File "/rcg/software/Linux/Ubuntu/16.04/amd64/TOOLS/TENSORFLOW/1.2.1-GPU-PY352/lib/python3.5/site-packages/tensorflow/python/client/session.py", line 942, in _run
allow_operation=False)
File "/rcg/software/Linux/Ubuntu/16.04/amd64/TOOLS/TENSORFLOW/1.2.1-GPU-PY352/lib/python3.5/site-packages/tensorflow/python/framework/ops.py", line 2584, in as_graph_element
return self._as_graph_element_locked(obj, allow_tensor, allow_operation)
File "/rcg/software/Linux/Ubuntu/16.04/amd64/TOOLS/TENSORFLOW/1.2.1-GPU-PY352/lib/python3.5/site-packages/tensorflow/python/framework/ops.py", line 2663, in _as_graph_element_locked
raise ValueError("Tensor %s is not an element of this graph." % obj)
ValueError: Tensor Tensor("Placeholder:0", shape=(1, 1), dtype=int32) is not an element of this graph.
答案 0 :(得分：14)
创建Model时，会话尚未恢复。 Model.__init__中定义的所有占位符，变量和操作都放在新图中，这使自己成为with块内的默认图。这是关键路线：
with tf.Graph().as_default():
...
这意味着tf.Graph()的此实例等于tf.get_default_graph()块内的with实例，但不在其之前或之后。从现在开始，存在两种不同的图形。
稍后创建会话并将图表还原到该会话时，您无法访问该会话中的tf.Graph()的前一个实例。这是一个简短的例子：
with tf.Graph().as_default() as graph:
var = tf.get_variable("var", shape=[3], initializer=tf.zeros_initializer)
# This works
with tf.Session(graph=graph) as sess:
sess.run(tf.global_variables_initializer())
print(sess.run(var)) # ok because `sess.graph == graph`
# This fails
saver = tf.train.import_meta_graph('/tmp/model.ckpt.meta')
with tf.Session() as sess:
saver.restore(sess, "/tmp/model.ckpt")
print(sess.run(var)) # var is from `graph`, not `sess.graph`!
处理此问题的最佳方法是为所有节点指定名称，例如'input'，'target'等保存模型，然后按名称查找恢复的图表中的节点，如下所示：
saver = tf.train.import_meta_graph('/tmp/model.ckpt.meta')
with tf.Session() as sess:
saver.restore(sess, "/tmp/model.ckpt")
input_data = sess.graph.get_tensor_by_name('input')
target = sess.graph.get_tensor_by_name('target')
此方法可确保所有节点都来自会话中的图形。
答案 1 :(得分：10)
尝试开始：
import tensorflow as tf
global graph,model
graph = tf.get_default_graph()
当您需要使用预测时：
with graph.as_default():
y = model.predict(X)
答案 2 :(得分：1)
在制作模型之前使用此行：
keras.backend.clear_session()
这将创建一个新图以用于新模型。
答案 3 :(得分：0)
内部
def LoadPredictor(save):
在加载模型后，只需添加model._make_predict_function()
所以函数变为：
def LoadPredictor(save):
with open(os.path.join(save, 'config.pkl'), 'rb') as f:
saved_args = cPickle.load(f)
with open(os.path.join(save, 'words_vocab.pkl'), 'rb') as f:
words, vocab = cPickle.load(f)
model = Model(saved_args, True)
model._make_predict_function()
return model, words, vocab
答案 4 :(得分：0)
如果您正在调用从外部模块调用Tensorflow的python函数，请确保您未将模型作为全局变量加载，否则可能无法及时加载以供使用。这发生在我从Flask服务器调用Tensorflow模型的过程中。
答案 5 :(得分：0)
在尝试使用另一个使用keras创建模型的类创建模型时遇到了这个问题。通过执行以下操作，我已解决此问题
import nn_classifierclass as cls
from keras import backend
for repeat in range(repeats):
backend.clear_session() ##NOTICE THIS
neural_net = cls.Classifier(.....)
neural_net.keras_fcn_classifier()
答案 6 :(得分：0)
对我来说，此问题已通过使用Keras的API保存和加载模型得到解决。我在代码中训练了多个模型，并且必须在特定条件下使用特定模型进行预测。
所以我在进行模型训练后将整个模型保存到HDF5文件中
# The '.h5' extension indicates that the model should be saved to HDF5.
model.save('my_model.h5')
，然后在预测时重新创建/重新加载保存的模型
my_model = tf.keras.models.load_model('my_model.h5')
这帮助我摆脱了
*Tensor not an element of this graph*
错误。