Commit missing example.gym.helpers module.

Fixes #91.

PiperOrigin-RevId: 350354657
Change-Id: I11e1af1b616f56792f7be2233377ce7d5e928bf4

examples/gym/helpers.py

@@ -0,0 +1,46 @@
+# python3
+# Copyright 2018 DeepMind Technologies Limited. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""OpenAI Gym environment factory."""
+
+from acme import wrappers
+import dm_env
+import gym
+
+TASKS = {
+    'debug': ['MountainCarContinuous-v0'],
+    'default': [
+        'HalfCheetah-v2', 'Hopper-v2', 'InvertedDoublePendulum-v2',
+        'InvertedPendulum-v2', 'Reacher-v2', 'Swimmer-v2', 'Walker2d-v2'
+    ],
+}
+
+
+def make_environment(
+    evaluation: bool = False,
+    task: str = 'MountainCarContinuous-v0') -> dm_env.Environment:
+  """Creates an OpenAI Gym environment."""
+  del evaluation
+
+  # Load the gym environment.
+  environment = gym.make(task)
+
+  # Make sure the environment obeys the dm_env.Environment interface.
+  environment = wrappers.GymWrapper(environment)
+  # Clip the action returned by the agent to the environment spec.
+  environment = wrappers.CanonicalSpecWrapper(environment, clip=True)
+  environment = wrappers.SinglePrecisionWrapper(environment)
+
+  return environment