Major Changes
com.unity.ml-agents (C)
- The `MLAgents` C namespace was renamed to `Unity.MLAgents`, and other nested namespaces were similarly renamed. (3843)
- The offset logic was removed from `DecisionRequester`. (3716)
- The signature of `Agent.Heuristic()` was changed to take a float array as a parameter, instead of returning the array. This was done to prevent a common source of error where users would return arrays of the wrong size. (3765)
- The communication API version has been bumped up to 1.0.0 and will use [Semantic Versioning](https://semver.org/) to do compatibility checks for communication between Unity and the Python process. (#3760)
- The obsolete `Agent` methods `GiveModel`, `Done`, `InitializeAgent`, `AgentAction` and `AgentReset` have been removed. (3770)
- The SideChannel API has changed:
- Introduced the `SideChannelManager` to register, unregister and access side channels. (3807)
- `Academy.FloatProperties` was replaced by `Academy.EnvironmentParameters`. See the [Migration Guide](https://github.com/Unity-Technologies/ml-agents/blob/release_1_docs/docs/Migrating.md) for more details on upgrading. (#3807)
- `SideChannel.OnMessageReceived` is now a protected method (was public). (3807)
- SideChannel IncomingMessages methods now take an optional default argument, which is used when trying to read more data than the message contains. (3751)
- Added a feature to allow sending stats from C environments to TensorBoard (and other python StatsWriters). To do this from your code, use `Academy.Instance.StatsRecorder.Add(key, value)`. (3660)
- `CameraSensorComponent.m_Grayscale` and `RenderTextureSensorComponent.m_Grayscale` were changed from `public` to `private`. These can still be accessed via their corresponding properties. (3808)
- Public fields and properties on several classes were renamed to follow Unity's C style conventions. All public fields and properties now use "PascalCase" instead of "camelCase"; for example, `Agent.maxStep` was renamed to `Agent.MaxStep`. For a full list of changes, see the pull request. (3828)
- `WriteAdapter` was renamed to `ObservationWriter`. If you have a custom `ISensor` implementation, you will need to change the signature of its `Write()` method. (3834)
- The Barracuda dependency was upgraded to 0.7.0-preview (which has breaking namespace and assembly name changes). (3875)
ml-agents / ml-agents-envs / gym-unity (Python)
- The `--load` and `--train` command-line flags have been deprecated. Training now happens by default, and use `--resume` to resume training instead of `--load`. (3705)
- The Jupyter notebooks have been removed from the repository. (3704)
- The multi-agent gym option was removed from the gym wrapper. For multi-agent scenarios, use the [Low Level Python API](https://github.com/Unity-Technologies/ml-agents/blob/release_1_docs/docs/Python-API.md). (#3681)
- The low level Python API has changed. You can look at the document [Low Level Python API documentation](https://github.com/Unity-Technologies/ml-agents/blob/release_1_docs/docs/Python-API.md) for more information. If you use `mlagents-learn` for training, this should be a transparent change. (#3681)
- Added ability to start training (initialize model weights) from a previous run ID. (3710)
- The GhostTrainer has been extended to support asymmetric games and the asymmetric example environment Strikers Vs. Goalie has been added. (3653)
- The `UnityEnv` class from the `gym-unity` package was renamed `UnityToGymWrapper` and no longer creates the `UnityEnvironment`. Instead, the `UnityEnvironment` must be passed as input to the constructor of `UnityToGymWrapper` (3812)
Minor Changes
com.unity.ml-agents (C)
- Added new 3-joint Worm ragdoll environment. (3798)
- `StackingSensor` was changed from `internal` visibility to `public`. (3701)
- The internal event `Academy.AgentSetStatus` was renamed to `Academy.AgentPreStep` and made public. (3716)
- Academy.InferenceSeed property was added. This is used to initialize the random number generator in ModelRunner, and is incremented for each ModelRunner. (3823)
- `Agent.GetObservations()` was added, which returns a read-only view of the observations added in `CollectObservations()`. (3825)
- `UnityRLCapabilities` was added to help inform users when RL features are mismatched between C and Python packages. (3831)
ml-agents / ml-agents-envs / gym-unity (Python)
- Format of console output has changed slightly and now matches the name of the model/summary directory. (3630, 3616)
- Renamed 'Generalization' feature to 'Environment Parameter Randomization'. (3646)
- Timer files now contain a dictionary of metadata, including things like the package version numbers. (3758)
- The way that UnityEnvironment decides the port was changed. If no port is specified, the behavior will depend on the `file_name` parameter. If it is `None`, 5004 (the editor port) will be used; otherwise 5005 (the base environment port) will be used. (3673)
- Running `mlagents-learn` with the same `--run-id` twice will no longer overwrite the existing files. (3705)
- Model updates can now happen asynchronously with environment steps for better performance. (3690)
- `num_updates` and `train_interval` for SAC were replaced with `steps_per_update`. (3690)
- The maximum compatible version of tensorflow was changed to allow tensorflow 2.1 and 2.2. This will allow use with python 3.8 using tensorflow 2.2.0rc3. (3830)
- `mlagents-learn` will no longer set the width and height of the executable window to 84x84 when no width nor height arguments are given. (3867)
Bug Fixes
com.unity.ml-agents (C)
- Fixed a display bug when viewing Demonstration files in the inspector. The shapes of the observations in the file now display correctly. (3771)
ml-agents / ml-agents-envs / gym-unity (Python)
- Fixed an issue where exceptions from environments provided a return code of 0. (3680)