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I was trying to load a saved model policy using the following code, but it ends with errors pasted below

saved_policy = tf.saved_model.load('policy_0')

Software versions:

• Tensorflow =2.3.0
• tf-agents = 0.6.0

Traceback (most recent call last): File "", line 1, in File "/lib/python3.6/site-packages/tensorflow/python/saved_model/load.py", line 603, in load return load_internal(export_dir, tags, options) File "/lib/python3.6/site-packages/tensorflow/python/saved_model/load.py", line 633, in load_internal ckpt_options) File "/lib/python3.6/site-packages/tensorflow/python/saved_model/load.py", line 130, in init self._load_all() File "/lib/python3.6/site-packages/tensorflow/python/saved_model/load.py", line 147, in _load_all self._setup_functions_structures() File "/lib/python3.6/site-packages/tensorflow/python/saved_model/load.py", line 191, in _setup_functions_structures original_outputs = coder.decode_proto(proto.output_signature) File "/lib/python3.6/site-packages/tensorflow/python/saved_model/nested_structure_coder.py", line 127, in decode_proto return self._map_structure(proto, self._get_decoders()) File "/lib/python3.6/site-packages/tensorflow/python/saved_model/nested_structure_coder.py", line 82, in _map_structure return do(pyobj, recursion_fn) File "/python3.6/site-packages/tensorflow/python/saved_model/nested_structure_coder.py", line 245, in do_decode items = [(pair.key, decode_fn(pair.value)) for pair in key_value_pairs] File "/lib/python3.6/site-packages/tensorflow/python/saved_model/nested_structure_coder.py", line 245, in items = [(pair.key, decode_fn(pair.value)) for pair in key_value_pairs] File "/lib/python3.6/site-packages/tensorflow/python/saved_model/nested_structure_coder.py", line 82, in _map_structure return do(pyobj, recursion_fn) File "/lib/python3.6/site-packages/tensorflow/python/saved_model/nested_structure_coder.py", line 552, in do_decode "version of TensorFlow.)" % type_spec_proto.type_spec_class_name) ValueError: The type '_DistributionTypeSpec' is not supported by this version of TensorFlow. (The object you are loading must have been created with a newer version of TensorFlow.) `

Can you try these: https://github.com/tensorflow/agents/blob/master/tf_agents/policies/policy_loader.py https://github.com/tensorflow/agents/blob/bdf6694dec482f8f894ee61dea750e1c0d48ad3e/tf_agents/policies/py_tf_eager_policy.py#L102

Using tf_agents.policies.policy_loader.load I can load policy. Thanks.

In this case, my concern is how I can use TF Serving if the policy can not be loaded with standard saved_model.load?

+1

I'm trying to convert a policy to TFLite and hit the same error. Not being fully 'Saved Model' is a real barrier.

Does it work on TF 2.4?

Just tried nightly. Didn't work.

_DistributionTypeSpec is a Tensorflow Probability object that we use in our policies because we serialize the _distribution() method as well. Tensorflow Probability renamed this object to _TFPTypeSpec about 4 months ago: https://github.com/tensorflow/probability/commit/2ffe65af9fbc1f1ce0a66a33073a243f3f089ed3

So in this case, the issue may be due to a policy saved with an older version of TFP but loaded with a recent version of TFP. I'll include the TFP team to see if they can make this backwards compatible.

Another possible issue here is that the type spec is only registered if you import tfp.experimental; unfortunately may be lazy-loaded (https://github.com/tensorflow/probability/blob/master/tensorflow_probability/python/init.py#L118). If you could run two experiments:

1. Import tensorflow_probability then try to do saved_model.load
2. Import tensorflow_probabitlity.experimental then try to do saved_model.load

Let us know if doing either of these fixes the issue.

Facing the same issue with tensorflow==2.4.1, tf_agents==0.7.1

And adding "import tensorflow_probability" fixes the issue (tf.saved_model.load works)

1. Import tensorflow_probability then try to do saved_model.load

I was facing a similar issue, not being able to load a policy. I added the import tensorflow_probability line at the beginning of the module, and it worked.