add back sonnet dependency. If sonnet is not installed, fall back to simpleAgent that does not need sonnet.

examples/pybullet/gym/agents/simpleAgentWithSonnet.py

@@ -0,0 +1,46 @@
+"""Loads a DDPG agent without too much external dependencies
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+import collections
+import numpy as np
+import tensorflow as tf
+
+import sonnet as snt
+from agents import actor_net
+
+class SimpleAgent():
+  def __init__(
+      self,
+      session,
+      ckpt_path,
+      actor_layer_size,
+      observation_size=(31,),
+      action_size=8,
+  ):
+    self._ckpt_path = ckpt_path
+    self._actor_layer_size = actor_layer_size
+    self._observation_size = observation_size
+    self._action_size = action_size
+    self._session = session
+    self._build()
+
+  def _build(self):
+    self._agent_net = actor_net.ActorNetwork(self._actor_layer_size, self._action_size)
+    self._obs = tf.placeholder(tf.float32, (31,))
+    with tf.name_scope('Act'):
+      batch_obs = snt.nest.pack_iterable_as(self._obs,
+                                            snt.nest.map(lambda x: tf.expand_dims(x, 0),
+                                                         snt.nest.flatten_iterable(self._obs)))
+      self._action = self._agent_net(batch_obs)
+      saver = tf.train.Saver()
+      saver.restore(
+          sess=self._session,
+          save_path=self._ckpt_path)
+
+  def __call__(self, observation):
+    out_action = self._session.run(self._action, feed_dict={self._obs: observation})
+    return out_action[0]