我正试图从答案中实现一个建议:Tensorflow:如何保存/恢复模型?
我有一个对象,它将tensorflow
模型包装为sklearn
样式。
import tensorflow as tf
class tflasso():
saver = tf.train.Saver()
def __init__(self,
learning_rate = 2e-2,
training_epochs = 5000,
display_step = 50,
BATCH_SIZE = 100,
ALPHA = 1e-5,
checkpoint_dir = "./",
):
...
def _create_network(self):
...
def _load_(self, sess, checkpoint_dir = None):
if checkpoint_dir:
self.checkpoint_dir = checkpoint_dir
print("loading a session")
ckpt = tf.train.get_checkpoint_state(self.checkpoint_dir)
if ckpt and ckpt.model_checkpoint_path:
self.saver.restore(sess, ckpt.model_checkpoint_path)
else:
raise Exception("no checkpoint found")
return
def fit(self, train_X, train_Y , load = True):
self.X = train_X
self.xlen = train_X.shape[1]
# n_samples = y.shape[0]
self._create_network()
tot_loss = self._create_loss()
optimizer = tf.train.AdagradOptimizer( self.learning_rate).minimize(tot_loss)
# Initializing the variables
init = tf.initialize_all_variables()
" training per se"
getb = batchgen( self.BATCH_SIZE)
yvar = train_Y.var()
print(yvar)
# Launch the graph
NUM_CORES = 3 # Choose how many cores to use.
sess_config = tf.ConfigProto(inter_op_parallelism_threads=NUM_CORES,
intra_op_parallelism_threads=NUM_CORES)
with tf.Session(config= sess_config) as sess:
sess.run(init)
if load:
self._load_(sess)
# Fit all training data
for epoch in range( self.training_epochs):
for (_x_, _y_) in getb(train_X, train_Y):
_y_ = np.reshape(_y_, [-1, 1])
sess.run(optimizer, feed_dict={ self.vars.xx: _x_, self.vars.yy: _y_})
# Display logs per epoch step
if (1+epoch) % self.display_step == 0:
cost = sess.run(tot_loss,
feed_dict={ self.vars.xx: train_X,
self.vars.yy: np.reshape(train_Y, [-1, 1])})
rsq = 1 - cost / yvar
logstr = "Epoch: {:4d}tcost = {:.4f}tR^2 = {:.4f}".format((epoch+1), cost, rsq)
print(logstr )
self.saver.save(sess, self.checkpoint_dir + 'model.ckpt',
global_step= 1+ epoch)
print("Optimization Finished!")
return self
当我运行时:
tfl = tflasso()
tfl.fit( train_X, train_Y , load = False)
我得到输出:
Epoch: 50 cost = 38.4705 R^2 = -1.2036
b1: 0.118122
Epoch: 100 cost = 26.4506 R^2 = -0.5151
b1: 0.133597
Epoch: 150 cost = 22.4330 R^2 = -0.2850
b1: 0.142261
Epoch: 200 cost = 20.0361 R^2 = -0.1477
b1: 0.147998
但是,当我尝试恢复参数时(即使不杀死对象):tfl.fit( train_X, train_Y , load = True)
我得到了奇怪的结果。首先,加载的值与保存的值不对应。
loading a session
loaded b1: 0.1 <------- Loaded another value than saved
Epoch: 50 cost = 30.8483 R^2 = -0.7670
b1: 0.137484
加载的正确方法是什么,并且可能首先检查保存的变量?
TL;DR:您应该尝试重新生成这个类,以便self.create_network()
(i)只调用一次,(ii)在构造tf.train.Saver()
之前调用。
这里有两个微妙的问题,这是由于代码结构和tf.train.Saver
构造函数的默认行为造成的。当您构造一个没有参数的保护程序时(如在代码中),它会收集程序中的当前变量集,并向图中添加操作以保存和恢复它们。在您的代码中,当您调用tflasso()
时,它将构造一个保护程序,并且不会有任何变量(因为create_network()
尚未被调用)。因此,检查点应该是空的。
第二个问题是;默认情况下—保存的检查点的格式是从变量的CCD_ 9属性到其当前值的映射。如果您创建两个同名变量,它们将自动被TensorFlow:"统一"
v = tf.Variable(..., name="weights")
assert v.name == "weights"
w = tf.Variable(..., name="weights")
assert v.name == "weights_1" # The "_1" is added by TensorFlow.
这样做的结果是,当您在对tfl.fit()
的第二次调用中调用self.create_network()
时,所有变量的名称都将与存储在检查点中的名称不同—或者如果保护程序是在网络之后构建的。(您可以通过将名称-Variable
字典传递给saver构造函数来避免这种行为,但这通常很尴尬。)
有两种主要的解决方法:
在对
tflasso.fit()
的每次调用中,通过定义新的tf.Graph
重新创建整个模型,然后在该图中构建网络并创建tf.train.Saver
。推荐创建网络,然后在
tflasso
构造函数中创建tf.train.Saver
,并在每次调用tflasso.fit()
时重用此图。请注意,您可能需要做更多的工作来重新组织事物(特别是,我不确定您对self.X
和self.xlen
做了什么),但应该可以通过占位符和喂食来实现这一点。