tensorflow:保存和恢复会话



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:

  1. 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

  2. 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.Xself.xlen做了什么),但应该可以通过占位符和喂食来实现这一点。

相关内容

  • 没有找到相关文章

最新更新