在Tensorflow中训练一个模型后:
如何拯救训练过的模型? 您以后如何恢复这个保存的模型?
在Tensorflow中训练一个模型后:
如何拯救训练过的模型? 您以后如何恢复这个保存的模型?
当前回答
正如Yaroslav所说,您可以通过导入图、手动创建变量,然后使用Saver来从graph_def和检查点进行恢复。
我实现这个是为了我个人使用,所以我想在这里分享一下代码。
链接:https://gist.github.com/nikitakit/6ef3b72be67b86cb7868
(当然,这是一种hack,并且不能保证以这种方式保存的模型在TensorFlow的未来版本中仍然是可读的。)
其他回答
使用tf.train.Saver保存模型。记住,如果想要减小模型大小,就需要指定var_list。val_list可以是:
特遣部队。trainable_variables或 tf.global_variables。
我的环境:Python 3.6, Tensorflow 1.3.0
虽然有很多解决方案,但大多数都是基于tf.train.Saver。当我们加载由Saver保存的.ckpt文件时,我们必须要么重新定义张量流网络,要么使用一些奇怪且难以记住的名称,例如:“placehold_0:0”,“密集/亚当/重量:0”。这里我推荐使用tf。saved_model,下面给出的一个最简单的例子,你可以从为TensorFlow模型服务中学到更多:
保存模型:
import tensorflow as tf
# define the tensorflow network and do some trains
x = tf.placeholder("float", name="x")
w = tf.Variable(2.0, name="w")
b = tf.Variable(0.0, name="bias")
h = tf.multiply(x, w)
y = tf.add(h, b, name="y")
sess = tf.Session()
sess.run(tf.global_variables_initializer())
# save the model
export_path = './savedmodel'
builder = tf.saved_model.builder.SavedModelBuilder(export_path)
tensor_info_x = tf.saved_model.utils.build_tensor_info(x)
tensor_info_y = tf.saved_model.utils.build_tensor_info(y)
prediction_signature = (
tf.saved_model.signature_def_utils.build_signature_def(
inputs={'x_input': tensor_info_x},
outputs={'y_output': tensor_info_y},
method_name=tf.saved_model.signature_constants.PREDICT_METHOD_NAME))
builder.add_meta_graph_and_variables(
sess, [tf.saved_model.tag_constants.SERVING],
signature_def_map={
tf.saved_model.signature_constants.DEFAULT_SERVING_SIGNATURE_DEF_KEY:
prediction_signature
},
)
builder.save()
加载模型:
import tensorflow as tf
sess=tf.Session()
signature_key = tf.saved_model.signature_constants.DEFAULT_SERVING_SIGNATURE_DEF_KEY
input_key = 'x_input'
output_key = 'y_output'
export_path = './savedmodel'
meta_graph_def = tf.saved_model.loader.load(
sess,
[tf.saved_model.tag_constants.SERVING],
export_path)
signature = meta_graph_def.signature_def
x_tensor_name = signature[signature_key].inputs[input_key].name
y_tensor_name = signature[signature_key].outputs[output_key].name
x = sess.graph.get_tensor_by_name(x_tensor_name)
y = sess.graph.get_tensor_by_name(y_tensor_name)
y_out = sess.run(y, {x: 3.0})
在大多数情况下,使用tf.train.Saver从磁盘保存和恢复是最好的选择:
... # build your model
saver = tf.train.Saver()
with tf.Session() as sess:
... # train the model
saver.save(sess, "/tmp/my_great_model")
with tf.Session() as sess:
saver.restore(sess, "/tmp/my_great_model")
... # use the model
您还可以保存/恢复图结构本身(详细信息请参阅MetaGraph文档)。默认情况下,保存程序将图形结构保存到.meta文件中。您可以调用import_meta_graph()来恢复它。它恢复图形结构并返回一个你可以用来恢复模型状态的保护程序:
saver = tf.train.import_meta_graph("/tmp/my_great_model.meta")
with tf.Session() as sess:
saver.restore(sess, "/tmp/my_great_model")
... # use the model
然而,在某些情况下,您需要更快的方法。例如,如果您实现了早期停止,那么您希望在训练期间每次模型改进时都保存检查点(在验证集上测量),然后如果一段时间内没有进展,则希望回滚到最佳模型。如果每次模型改进时都将其保存到磁盘,则会极大地降低训练速度。诀窍是将变量状态保存到内存中,然后稍后恢复它们:
... # build your model
# get a handle on the graph nodes we need to save/restore the model
graph = tf.get_default_graph()
gvars = graph.get_collection(tf.GraphKeys.GLOBAL_VARIABLES)
assign_ops = [graph.get_operation_by_name(v.op.name + "/Assign") for v in gvars]
init_values = [assign_op.inputs[1] for assign_op in assign_ops]
with tf.Session() as sess:
... # train the model
# when needed, save the model state to memory
gvars_state = sess.run(gvars)
# when needed, restore the model state
feed_dict = {init_value: val
for init_value, val in zip(init_values, gvars_state)}
sess.run(assign_ops, feed_dict=feed_dict)
A quick explanation: when you create a variable X, TensorFlow automatically creates an assignment operation X/Assign to set the variable's initial value. Instead of creating placeholders and extra assignment ops (which would just make the graph messy), we just use these existing assignment ops. The first input of each assignment op is a reference to the variable it is supposed to initialize, and the second input (assign_op.inputs[1]) is the initial value. So in order to set any value we want (instead of the initial value), we need to use a feed_dict and replace the initial value. Yes, TensorFlow lets you feed a value for any op, not just for placeholders, so this works fine.
tensorflow - 2.0
这很简单。
import tensorflow as tf
SAVE
model.save("model_name")
恢复
model = tf.keras.models.load_model('model_name')
无论你想把模型保存在哪里,
self.saver = tf.train.Saver()
with tf.Session() as sess:
sess.run(tf.global_variables_initializer())
...
self.saver.save(sess, filename)
确保你所有的任务。变量有名称,因为您可能希望稍后使用它们的名称来恢复它们。 在你想预测的地方,
saver = tf.train.import_meta_graph(filename)
name = 'name given when you saved the file'
with tf.Session() as sess:
saver.restore(sess, name)
print(sess.run('W1:0')) #example to retrieve by variable name
确保该保护程序在相应的会话中运行。 请记住,如果使用tf.train.latest_checkpoint('./'),那么将只使用最新的检查点。