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我正在嘗試使用張量流來訓練序列模型。我在教程中看到,桶有助於加速培訓。到目前爲止,我只能使用一個桶進行訓練,並且只使用一個gpu和多個桶來使用或多或少的開箱即用代碼,但是當我嘗試使用具有多個gpus的多個桶時,出現錯誤,指出 參數無效:您必須養活佔位符張量「gpu_scope_0/encoder50_gpu0」與D型的值INT32帶桶的Tensorflow錯誤
從錯誤中,我可以告訴大家,我不是正確聲明input_feed,所以它期待的輸入是的每次最大桶的大小。不過,我很困惑爲什麼會出現這種情況,因爲在我正在調整的示例中,它在初始化input_feed的佔位符時會執行相同的操作。據我所知,教程也初始化爲最大容量的桶,但是當我使用教程的代碼時,這個錯誤不會發生。
以下是我認爲是相關的初始化代碼:
self.encoder_inputs = [[] for _ in xrange(self.num_gpus)]
self.decoder_inputs = [[] for _ in xrange(self.num_gpus)]
self.target_weights = [[] for _ in xrange(self.num_gpus)]
self.scope_prefix = "gpu_scope"
for j in xrange(self.num_gpus):
with tf.device("/gpu:%d" % (self.gpu_offset + j)):
with tf.name_scope('%s_%d' % (self.scope_prefix, j)) as scope:
for i in xrange(buckets[-1][0]): # Last bucket is the biggest one.
self.encoder_inputs[j].append(tf.placeholder(tf.int32, shape=[None],
name="encoder{0}_gpu{1}".format(i,j)))
for i in xrange(buckets[-1][1] + 1):
self.decoder_inputs[j].append(tf.placeholder(tf.int32, shape=[None],
name="decoder{0}_gpu{1}".format(i,j)))
self.target_weights[j].append(tf.placeholder(tf.float32, shape=[None],
name="weight{0}_gpu{1}".format(i,j)))
# Our targets are decoder inputs shifted by one.
self.losses = []
self.outputs = []
# The following loss computation creates the neural network. The specified
# device hosts the trainable tf parameters.
bucket = buckets[0]
i = 0
with tf.device(param_device):
output, loss = tf.nn.seq2seq.model_with_buckets(self.encoder_inputs[i], self.decoder_inputs[i],
[self.decoder_inputs[i][k + 1] for k in
xrange(len(self.decoder_inputs[i]) - 1)],
self.target_weights[0], buckets,
lambda x, y: seq2seq_f(x, y, True),
softmax_loss_function=self.softmax_loss_function)
bucket = buckets[0]
self.encoder_states = []
with tf.device('/gpu:%d' % self.gpu_offset):
with variable_scope.variable_scope(variable_scope.get_variable_scope(),
reuse=True):
self.encoder_outputs, self.encoder_states = get_encoder_outputs(self,
self.encoder_inputs[0])
if not forward_only:
self.grads = []
print ("past line 297")
done_once = False
for i in xrange(self.num_gpus):
with tf.device("/gpu:%d" % (self.gpu_offset + i)):
with tf.name_scope("%s_%d" % (self.scope_prefix, i)) as scope:
with variable_scope.variable_scope(variable_scope.get_variable_scope(), reuse=True):
#for j, bucket in enumerate(buckets):
output, loss = tf.nn.seq2seq.model_with_buckets(self.encoder_inputs[i],
self.decoder_inputs[i],
[self.decoder_inputs[i][k + 1] for k in
xrange(len(self.decoder_inputs[i]) - 1)],
self.target_weights[i], buckets,
lambda x, y: seq2seq_f(x, y, True),
softmax_loss_function=self.softmax_loss_function)
self.losses.append(loss)
self.outputs.append(output)
# Training outputs and losses.
if forward_only:
self.outputs, self.losses = tf.nn.seq2seq.model_with_buckets(
self.encoder_inputs, self.decoder_inputs,
[self.decoder_inputs[0][k + 1] for k in xrange(buckets[0][1])],
self.target_weights, buckets, lambda x, y: seq2seq_f(x, y, True),
softmax_loss_function=self.softmax_loss_function)
# If we use output projection, we need to project outputs for decoding.
if self.output_projection is not None:
for b in xrange(len(buckets)):
self.outputs[b] = [
tf.matmul(output, self.output_projection[0]) + self.output_projection[1]
for output in self.outputs[b]
]
else:
self.bucket_grads = []
self.gradient_norms = []
params = tf.trainable_variables()
opt = tf.train.GradientDescentOptimizer(self.learning_rate)
self.updates = []
with tf.device(aggregation_device):
for g in xrange(self.num_gpus):
for b in xrange(len(buckets)):
gradients = tf.gradients(self.losses[g][b], params)
clipped_grads, norm = tf.clip_by_global_norm(gradients, max_gradient_norm)
self.gradient_norms.append(norm)
self.updates.append(
opt.apply_gradients(zip(clipped_grads, params), global_step=self.global_step))
,並在數據餵奶時,以下是相關代碼:眼下
input_feed = {}
for i in xrange(self.num_gpus):
for l in xrange(encoder_size):
input_feed[self.encoder_inputs[i][l].name] = encoder_inputs[i][l]
for l in xrange(decoder_size):
input_feed[self.decoder_inputs[i][l].name] = decoder_inputs[i][l]
input_feed[self.target_weights[i][l].name] = target_weights[i][l]
# Since our targets are decoder inputs shifted by one, we need one more.
last_target = self.decoder_inputs[i][decoder_size].name
input_feed[last_target] = np.zeros([self.batch_size], dtype=np.int32)
last_weight = self.target_weights[i][decoder_size].name
input_feed[last_weight] = np.zeros([self.batch_size], dtype=np.float32)
# Output feed: depends on whether we do a backward step or not.
if not forward_only:
output_feed = [self.updates[bucket_id], self.gradient_norms[bucket_id], self.losses[bucket_id]]
else:
output_feed = [self.losses[bucket_id]] # Loss for this batch.
for l in xrange(decoder_size): # Output logits.
output_feed.append(self.outputs[0][l])
我只考慮填充每個輸入達到桶的大小,但我認爲這會失去一些桶裝的優點