Tensorflow + Jupyterのsave & restore時のトラブルとその回避方法
Tensorflowでモデルを保存しようとする場合にsaveしたモデルをrestoreすることができないトラブルに遭遇した。
保存側:
import tensorflow as tf import numpy as np from tensorflow.examples.tutorials.mnist import input_data x = tf.placeholder(tf.float32, [None, 784]) W = tf.Variable(tf.zeros([784, 10])) b = tf.Variable(tf.zeros([10])) y = tf.nn.softmax(tf.matmul(x, W) + b) y_ = tf.placeholder(tf.float32, [None, 10]) cross_entropy = tf.reduce_mean(-tf.reduce_sum(y_ * tf.log(y), reduction_indices=[1])) train_step = tf.train.GradientDescentOptimizer(0.5).minimize(cross_entropy) saver = tf.train.Saver() sess = tf.InteractiveSession() tf.global_variables_initializer().run() mnist = input_data.read_data_sets("MNIST_data/", one_hot=True) for _ in range(3): print(_) batch_xs, batch_ys = mnist.train.next_batch(100) sess.run(train_step, feed_dict={x: batch_xs, y_: batch_ys}) save_path = saver.save(sess, "tmp/model.ckpt") print(save_path) print(sess.run(b)) print(sess.run(W))
読込側:
import tensorflow as tf import numpy as np x = tf.placeholder(tf.float32, [None, 784]) W = tf.Variable(tf.zeros([784, 10])) b = tf.Variable(tf.zeros([10])) y = tf.nn.softmax(tf.matmul(x, W) + b) y_ = tf.placeholder(tf.float32, [None, 10]) cross_entropy = tf.reduce_mean(-tf.reduce_sum(y_ * tf.log(y), reduction_indices=[1])) train_step = tf.train.GradientDescentOptimizer(0.5).minimize(cross_entropy) saver = tf.train.Saver() with tf.Session() as sess: # Restore variables from disk. saver.restore(sess, "tmp/model.ckpt") print("Model restored.") print(sess.run(b)) print(sess.run(W))
上記のコードはmnist sampleにsaveとrestoreを追加したもの。シェル上では正しく動作するのだが、jupyter上で動作させると
NotFoundError: Key Variable_43 not found in checkpoint
というエラーが発生する。(43の部分は実行毎に異なる)
StackOverflowには同様の事象の報告が上がっている。Googleのエンジニアからの回答によると、 ・Jupyterがコードの再実行時のパフォーマンスを上げるために勝手に変数をコピーする=> ・その結果、Tensorflowが名前の重複を避けるために新しい名前をアサインして別Variablesが増える ということが起きているようです。
これを避けるために、3つの方法が提示されています。
モデルの構築を始める前に
tf.reset_default_graph()
を呼び出す。(defaultとして設定されているGraphが消える点に注意)tf.train.Saver()
を呼び出す際に、保存するVariableを明示的に指定する。例としてはsaver = tf.train.Saver(var_list={"b1": b1, "W1": W1, "b2": b2, "W2": W2})
が紹介されていますが、こちらのように、Variableの宣言時にtrainable=True
を宣言し、tf.trainable_variables()
をSaver
に渡す方法もあるようですGraphのスコープを
with tf.Graph().as_default():
で明示的に指定し、その中でモデルの宣言とrestoreを行う
副作用が少なそうで、行儀が良さそうなのは2かな..という気がするのでこれでやっています。 Tensorflowのsaveとrestoreについては、Saverコンストラクタの呼び出しタイミングがセンシティブだったりするので色々注意が必要ですね。
補足: エラー詳細
INFO:tensorflow:Restoring parameters from tmp/model.ckpt --------------------------------------------------------------------------- NotFoundError Traceback (most recent call last) <ipython-input-36-1322488c39ce> in <module>() 12 with tf.Session() as sess: 13 # Restore variables from disk. ---> 14 saver.restore(sess, "tmp/model.ckpt") 15 print("Model restored.") 16 /Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/training/saver.pyc in restore(self, sess, save_path) 1455 logging.info("Restoring parameters from %s", save_path) 1456 sess.run(self.saver_def.restore_op_name, -> 1457 {self.saver_def.filename_tensor_name: save_path}) 1458 1459 @staticmethod /Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in run(self, fetches, feed_dict, options, run_metadata) 776 try: 777 result = self._run(None, fetches, feed_dict, options_ptr, --> 778 run_metadata_ptr) 779 if run_metadata: 780 proto_data = tf_session.TF_GetBuffer(run_metadata_ptr) /Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in _run(self, handle, fetches, feed_dict, options, run_metadata) 980 if final_fetches or final_targets: 981 results = self._do_run(handle, final_targets, final_fetches, --> 982 feed_dict_string, options, run_metadata) 983 else: 984 results = [] /Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in _do_run(self, handle, target_list, fetch_list, feed_dict, options, run_metadata) 1030 if handle is None: 1031 return self._do_call(_run_fn, self._session, feed_dict, fetch_list, -> 1032 target_list, options, run_metadata) 1033 else: 1034 return self._do_call(_prun_fn, self._session, handle, feed_dict, /Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in _do_call(self, fn, *args) 1050 except KeyError: 1051 pass -> 1052 raise type(e)(node_def, op, message) 1053 1054 def _extend_graph(self): NotFoundError: Key Variable_43 not found in checkpoint [[Node: save_21/RestoreV2_38 = RestoreV2[dtypes=[DT_FLOAT], _device="/job:localhost/replica:0/task:0/cpu:0"](_recv_save_21/Const_0, save_21/RestoreV2_38/tensor_names, save_21/RestoreV2_38/shape_and_slices)]] Caused by op u'save_21/RestoreV2_38', defined at: File "/Users/miz/.pyenv/versions/2.7.11/lib/python2.7/runpy.py", line 162, in _run_module_as_main "__main__", fname, loader, pkg_name) File "/Users/miz/.pyenv/versions/2.7.11/lib/python2.7/runpy.py", line 72, in _run_code exec code in run_globals File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel_launcher.py", line 16, in <module> app.launch_new_instance() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/traitlets/config/application.py", line 658, in launch_instance app.start() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel/kernelapp.py", line 477, in start ioloop.IOLoop.instance().start() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/zmq/eventloop/ioloop.py", line 177, in start super(ZMQIOLoop, self).start() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tornado/ioloop.py", line 888, in start handler_func(fd_obj, events) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tornado/stack_context.py", line 277, in null_wrapper return fn(*args, **kwargs) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 440, in _handle_events self._handle_recv() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 472, in _handle_recv self._run_callback(callback, msg) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 414, in _run_callback callback(*args, **kwargs) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tornado/stack_context.py", line 277, in null_wrapper return fn(*args, **kwargs) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 283, in dispatcher return self.dispatch_shell(stream, msg) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 235, in dispatch_shell handler(stream, idents, msg) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 399, in execute_request user_expressions, allow_stdin) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel/ipkernel.py", line 196, in do_execute res = shell.run_cell(code, store_history=store_history, silent=silent) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/ipykernel/zmqshell.py", line 533, in run_cell return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2717, in run_cell interactivity=interactivity, compiler=compiler, result=result) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2821, in run_ast_nodes if self.run_code(code, result): File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2881, in run_code exec(code_obj, self.user_global_ns, self.user_ns) File "<ipython-input-36-1322488c39ce>", line 10, in <module> saver = tf.train.Saver() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 1056, in __init__ self.build() File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 1086, in build restore_sequentially=self._restore_sequentially) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 691, in build restore_sequentially, reshape) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 407, in _AddRestoreOps tensors = self.restore_op(filename_tensor, saveable, preferred_shard) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 247, in restore_op [spec.tensor.dtype])[0]) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/ops/gen_io_ops.py", line 669, in restore_v2 dtypes=dtypes, name=name) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 768, in apply_op op_def=op_def) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2336, in create_op original_op=self._default_original_op, op_def=op_def) File "/Users/miz/.pyenv/versions/2.7.11/envs/tensorflow_test/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1228, in __init__ self._traceback = _extract_stack() NotFoundError (see above for traceback): Key Variable_43 not found in checkpoint [[Node: save_21/RestoreV2_38 = RestoreV2[dtypes=[DT_FLOAT], _device="/job:localhost/replica:0/task:0/cpu:0"](_recv_save_21/Const_0, save_21/RestoreV2_38/tensor_names, save_21/RestoreV2_38/shape_and_slices)]]