[Python] Restoring TensorFlow model

Discussão em 'Python' iniciado por Stack, Abril 5, 2025.

  1. Stack

    Stack Membro Participativo

    I'm trying to restore TensorFlow model. I followed this example: http://nasdag.github.io/blog/2016/01/19/classifying-bees-with-google-tensorflow/

    At the end of the code in the example I added these lines:

    saver = tf.train.Saver()
    save_path = saver.save(sess, "model.ckpt")
    print("Model saved in file: %s" % save_path)


    Two files were created: checkpoint and model.ckpt.

    In a new python file (tomas_bees_predict.py), I have this code:

    import tensorflow as tf

    saver = tf.train.Saver()

    with tf.Session() as sess:
    # Restore variables from disk.
    saver.restore(sess, "model.ckpt")
    print("Model restored.")


    However when I execute the code, I get this error:

    Traceback (most recent call last):
    File "tomas_bees_predict.py", line 3, in <module>
    saver = tf.train.Saver()
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 705, in __init__
    raise ValueError("No variables to save")


    ValueError: No variables to save

    Is there a way to read mode.ckpt file and see what variables are saved? Or maybe someone can help with saving the model and restoring it based on the example described above?

    EDIT 1:

    I think I tried running the same code in order to recreate model structure and I was getting the error. I think it could be related to the fact that code described here isn't using named variables: http://nasdag.github.io/blog/2016/01/19/classifying-bees-with-google-tensorflow/

    def weight_variable(shape):
    initial = tf.truncated_normal(shape, stddev=0.1)
    return tf.Variable(initial)

    def bias_variable(shape):
    initial = tf.constant(0.1, shape=shape)
    return tf.Variable(initial)


    So I did this experiment. I wrote two versions of the code (with and without named variables) to save the model and the code to restore the model.

    tensor_save_named_vars.py:

    import tensorflow as tf

    # Create some variables.
    v1 = tf.Variable(1, name="v1")
    v2 = tf.Variable(2, name="v2")

    # Add an op to initialize the variables.
    init_op = tf.initialize_all_variables()

    # Add ops to save and restore all the variables.
    saver = tf.train.Saver()

    # Later, launch the model, initialize the variables, do some work, save the
    # variables to disk.
    with tf.Session() as sess:
    sess.run(init_op)
    print "v1 = ", v1.eval()
    print "v2 = ", v2.eval()
    # Save the variables to disk.
    save_path = saver.save(sess, "/tmp/model.ckpt")
    print "Model saved in file: ", save_path


    tensor_save_not_named_vars.py:

    import tensorflow as tf

    # Create some variables.
    v1 = tf.Variable(1)
    v2 = tf.Variable(2)

    # Add an op to initialize the variables.
    init_op = tf.initialize_all_variables()

    # Add ops to save and restore all the variables.
    saver = tf.train.Saver()

    # Later, launch the model, initialize the variables, do some work, save the
    # variables to disk.
    with tf.Session() as sess:
    sess.run(init_op)
    print "v1 = ", v1.eval()
    print "v2 = ", v2.eval()
    # Save the variables to disk.
    save_path = saver.save(sess, "/tmp/model.ckpt")
    print "Model saved in file: ", save_path


    tensor_restore.py:

    import tensorflow as tf

    # Create some variables.
    v1 = tf.Variable(0, name="v1")
    v2 = tf.Variable(0, name="v2")

    # Add ops to save and restore all the variables.
    saver = tf.train.Saver()

    # Later, launch the model, use the saver to restore variables from disk, and
    # do some work with the model.
    with tf.Session() as sess:
    # Restore variables from disk.
    saver.restore(sess, "/tmp/model.ckpt")
    print "Model restored."
    print "v1 = ", v1.eval()
    print "v2 = ", v2.eval()


    Here is what I get when I execute this code:

    $ python tensor_save_named_vars.py

    I tensorflow/core/common_runtime/local_device.cc:40] Local device intra op parallelism threads: 4
    I tensorflow/core/common_runtime/direct_session.cc:58] Direct session inter op parallelism threads: 4
    v1 = 1
    v2 = 2
    Model saved in file: /tmp/model.ckpt

    $ python tensor_restore.py

    I tensorflow/core/common_runtime/local_device.cc:40] Local device intra op parallelism threads: 4
    I tensorflow/core/common_runtime/direct_session.cc:58] Direct session inter op parallelism threads: 4
    Model restored.
    v1 = 1
    v2 = 2

    $ python tensor_save_not_named_vars.py

    I tensorflow/core/common_runtime/local_device.cc:40] Local device intra op parallelism threads: 4
    I tensorflow/core/common_runtime/direct_session.cc:58] Direct session inter op parallelism threads: 4
    v1 = 1
    v2 = 2
    Model saved in file: /tmp/model.ckpt

    $ python tensor_restore.py
    I tensorflow/core/common_runtime/local_device.cc:40] Local device intra op parallelism threads: 4
    I tensorflow/core/common_runtime/direct_session.cc:58] Direct session inter op parallelism threads: 4
    W tensorflow/core/common_runtime/executor.cc:1076] 0x7ff953881e40 Compute status: Not found: Tensor name "v2" not found in checkpoint files /tmp/model.ckpt
    [[Node: save/restore_slice_1 = RestoreSlice[dt=DT_INT32, preferred_shard=-1, _device="/job:localhost/replica:0/task:0/cpu:0"](_recv_save/Const_0, save/restore_slice_1/tensor_name, save/restore_slice_1/shape_and_slice)]]
    W tensorflow/core/common_runtime/executor.cc:1076] 0x7ff953881e40 Compute status: Not found: Tensor name "v1" not found in checkpoint files /tmp/model.ckpt
    [[Node: save/restore_slice = RestoreSlice[dt=DT_INT32, preferred_shard=-1, _device="/job:localhost/replica:0/task:0/cpu:0"](_recv_save/Const_0, save/restore_slice/tensor_name, save/restore_slice/shape_and_slice)]]
    Traceback (most recent call last):
    File "tensor_restore.py", line 14, in <module>
    saver.restore(sess, "/tmp/model.ckpt")
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 891, in restore
    sess.run([self._restore_op_name], {self._filename_tensor_name: save_path})
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 368, in run
    results = self._do_run(target_list, unique_fetch_targets, feed_dict_string)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 444, in _do_run
    e.code)
    tensorflow.python.framework.errors.NotFoundError: Tensor name "v2" not found in checkpoint files /tmp/model.ckpt
    [[Node: save/restore_slice_1 = RestoreSlice[dt=DT_INT32, preferred_shard=-1, _device="/job:localhost/replica:0/task:0/cpu:0"](_recv_save/Const_0, save/restore_slice_1/tensor_name, save/restore_slice_1/shape_and_slice)]]
    Caused by op u'save/restore_slice_1', defined at:
    File "tensor_restore.py", line 8, in <module>
    saver = tf.train.Saver()
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 713, in __init__
    restore_sequentially=restore_sequentially)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 432, in build
    filename_tensor, vars_to_save, restore_sequentially, reshape)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 191, in _AddRestoreOps
    values = self.restore_op(filename_tensor, vs, preferred_shard)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/training/saver.py", line 106, in restore_op
    preferred_shard=preferred_shard)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/io_ops.py", line 189, in _restore_slice
    preferred_shard, name=name)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/gen_io_ops.py", line 271, in _restore_slice
    preferred_shard=preferred_shard, name=name)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/op_def_library.py", line 664, in apply_op
    op_def=op_def)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1834, in create_op
    original_op=self._default_original_op, op_def=op_def)
    File "/usr/local/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1043, in __init__
    self._traceback = _extract_stack()


    So perhaps the original code (see the external link above) could be modified to something like this:

    def weight_variable(shape):
    initial = tf.truncated_normal(shape, stddev=0.1)
    weight_var = tf.Variable(initial, name="weight_var")
    return weight_var

    def bias_variable(shape):
    initial = tf.constant(0.1, shape=shape)
    bias_var = tf.Variable(initial, name="bias_var")
    return bias_var


    But then the question I have: is restoring weight_var and bias_var variables sufficient to implement the prediction? I did the training on the powerful machine with GPU and I would like to copy the model to the less powerful computer without GPU to run predictions.

    Continue reading...

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