using System; using System.Collections.Generic; using UnityEngine; using Barracuda; using MLAgents.Sensors; using MLAgents.Demonstrations; using MLAgents.Policies; namespace MLAgents { /// /// Struct that contains all the information for an Agent, including its /// observations, actions and current status. /// internal struct AgentInfo { /// /// Keeps track of the last vector action taken by the Brain. /// public float[] storedVectorActions; /// /// For discrete control, specifies the actions that the agent cannot take. Is true if /// the action is masked. /// public bool[] discreteActionMasks; /// /// Current agent reward. /// public float reward; /// /// Whether the agent is done or not. /// public bool done; /// /// Whether the agent has reached its max step count for this episode. /// public bool maxStepReached; /// /// Episode identifier each agent receives at every reset. It is used /// to separate between different agents in the environment. /// public int episodeId; } /// /// Struct that contains the action information sent from the Brain to the /// Agent. /// internal struct AgentAction { public float[] vectorActions; } /// /// Agent MonoBehaviour class that is attached to a Unity GameObject, making it /// an Agent. An agent produces observations and takes actions in the /// environment. Observations are determined by the cameras attached /// to the agent in addition to the vector observations implemented by the /// user in . /// On the other hand, actions are determined by decisions produced by a Policy. /// Currently, this class is expected to be extended to implement the desired agent behavior. /// /// /// Simply speaking, an agent roams through an environment and at each step /// of the environment extracts its current observation, sends them to its /// policy and in return receives an action. In practice, /// however, an agent need not send its observation at every step since very /// little may have changed between successive steps. /// /// At any step, an agent may be considered done due to a variety of reasons: /// - The agent reached an end state within its environment. /// - The agent reached the maximum # of steps (i.e. timed out). /// - The academy reached the maximum # of steps (forced agent to be done). /// /// Here, an agent reaches an end state if it completes its task successfully /// or somehow fails along the way. In the case where an agent is done before /// the academy, it either resets and restarts, or just lingers until the /// academy is done. /// /// An important note regarding steps and episodes is due. Here, an agent step /// corresponds to an academy step, which also corresponds to Unity /// environment step (i.e. each FixedUpdate call). This is not the case for /// episodes. The academy controls the global episode count and each agent /// controls its own local episode count and can reset and start a new local /// episode independently (based on its own experience). Thus an academy /// (global) episode can be viewed as the upper-bound on an agents episode /// length and that within a single global episode, an agent may have completed /// multiple local episodes. Consequently, if an agent max step is /// set to a value larger than the academy max steps value, then the academy /// value takes precedence (since the agent max step will never be reached). /// /// Lastly, note that at any step the policy to the agent is allowed to /// change model with . /// /// Implementation-wise, it is required that this class is extended and the /// virtual methods overridden. For sample implementations of agent behavior, /// see the Examples/ directory within this Unity project. /// [HelpURL("https://github.com/Unity-Technologies/ml-agents/blob/master/" + "docs/Learning-Environment-Design-Agents.md")] [Serializable] [RequireComponent(typeof(BehaviorParameters))] public class Agent : MonoBehaviour, ISerializationCallbackReceiver { IPolicy m_Brain; BehaviorParameters m_PolicyFactory; /// This code is here to make the upgrade path for users using maxStep /// easier. We will hook into the Serialization code and make sure that /// agentParameters.maxStep and this.maxStep are in sync. [Serializable] internal struct AgentParameters { public int maxStep; } [SerializeField][HideInInspector] internal AgentParameters agentParameters; [SerializeField][HideInInspector] internal bool hasUpgradedFromAgentParameters; /// /// The maximum number of steps the agent takes before being done. /// /// /// If set to 0, the agent can only be set to done programmatically (or /// when the Academy is done). /// If set to any positive integer, the agent will be set to done after /// that many steps. Note that setting the max step to a value greater /// than the academy max step value renders it useless. /// [HideInInspector] public int maxStep; /// Current Agent information (message sent to Brain). AgentInfo m_Info; /// Current Agent action (message sent from Brain). AgentAction m_Action; /// Represents the reward the agent accumulated during the current step. /// It is reset to 0 at the beginning of every step. /// Should be set to a positive value when the agent performs a "good" /// action that we wish to reinforce/reward, and set to a negative value /// when the agent performs a "bad" action that we wish to punish/deter. /// Additionally, the magnitude of the reward should not exceed 1.0 float m_Reward; /// Keeps track of the cumulative reward in this episode. float m_CumulativeReward; /// Whether or not the agent requests an action. bool m_RequestAction; /// Whether or not the agent requests a decision. bool m_RequestDecision; /// Keeps track of the number of steps taken by the agent in this episode. /// Note that this value is different for each agent, and may not overlap /// with the step counter in the Academy, since agents reset based on /// their own experience. int m_StepCount; /// Episode identifier each agent receives. It is used /// to separate between different agents in the environment. /// This Id will be changed every time the Agent resets. int m_EpisodeId; /// Whether or not the Agent has been initialized already bool m_Initialized; /// Keeps track of the actions that are masked at each step. DiscreteActionMasker m_ActionMasker; /// /// Set of DemonstrationWriters that the Agent will write its step information to. /// If you use a DemonstrationRecorder component, this will automatically register its DemonstrationWriter. /// You can also add your own DemonstrationWriter by calling /// DemonstrationRecorder.AddDemonstrationWriterToAgent() /// internal ISet DemonstrationWriters = new HashSet(); /// /// List of sensors used to generate observations. /// Currently generated from attached SensorComponents, and a legacy VectorSensor /// internal List sensors; /// /// VectorSensor which is written to by AddVectorObs /// internal VectorSensor collectObservationsSensor; /// /// Called when the attached becomes enabled and active. /// protected virtual void OnEnable() { LazyInitialize(); } /// /// /// public void OnBeforeSerialize() { // Manages a serialization upgrade issue from v0.13 to v0.14 where maxStep moved // from AgentParameters (since removed) to Agent if (maxStep == 0 && maxStep != agentParameters.maxStep && !hasUpgradedFromAgentParameters) { maxStep = agentParameters.maxStep; } hasUpgradedFromAgentParameters = true; } /// /// /// public void OnAfterDeserialize() { // Manages a serialization upgrade issue from v0.13 to v0.14 where maxStep moved // from AgentParameters (since removed) to Agent if (maxStep == 0 && maxStep != agentParameters.maxStep && !hasUpgradedFromAgentParameters) { maxStep = agentParameters.maxStep; } hasUpgradedFromAgentParameters = true; } /// /// Initializes the agent. Can be safely called multiple times. /// public void LazyInitialize() { if (m_Initialized) { return; } m_Initialized = true; // Grab the "static" properties for the Agent. m_EpisodeId = EpisodeIdCounter.GetEpisodeId(); m_PolicyFactory = GetComponent(); m_Info = new AgentInfo(); m_Action = new AgentAction(); sensors = new List(); Academy.Instance.AgentIncrementStep += AgentIncrementStep; Academy.Instance.AgentSendState += SendInfo; Academy.Instance.DecideAction += DecideAction; Academy.Instance.AgentAct += AgentStep; Academy.Instance.AgentForceReset += _AgentReset; m_Brain = m_PolicyFactory.GeneratePolicy(Heuristic); ResetData(); Initialize(); InitializeSensors(); // The first time the Academy resets, all Agents in the scene will be // forced to reset through the event. // To avoid the Agent resetting twice, the Agents will not begin their // episode when initializing until after the Academy had its first reset. if (Academy.Instance.TotalStepCount != 0) { OnEpisodeBegin(); } } /// /// Reason that the Agent is being considered "done" /// enum DoneReason { /// /// The method was called. /// DoneCalled, /// /// The max steps for the Agent were reached. /// MaxStepReached, /// /// The Agent was disabled /// Disabled, } /// /// Called when the attached becomes disabled and inactive. /// protected virtual void OnDisable() { DemonstrationWriters.Clear(); // If Academy.Dispose has already been called, we don't need to unregister with it. // We don't want to even try, because this will lazily create a new Academy! if (Academy.IsInitialized) { Academy.Instance.AgentIncrementStep -= AgentIncrementStep; Academy.Instance.AgentSendState -= SendInfo; Academy.Instance.DecideAction -= DecideAction; Academy.Instance.AgentAct -= AgentStep; Academy.Instance.AgentForceReset -= _AgentReset; } NotifyAgentDone(DoneReason.Disabled); m_Brain?.Dispose(); m_Initialized = false; } void NotifyAgentDone(DoneReason doneReason) { m_Info.episodeId = m_EpisodeId; m_Info.reward = m_Reward; m_Info.done = true; m_Info.maxStepReached = doneReason == DoneReason.MaxStepReached; // Request the last decision with no callbacks // We request a decision so Python knows the Agent is done immediately m_Brain?.RequestDecision(m_Info, sensors); // We also have to write any to any DemonstationStores so that they get the "done" flag. foreach (var demoWriter in DemonstrationWriters) { demoWriter.Record(m_Info, sensors); } if (doneReason != DoneReason.Disabled) { // We don't want to udpate the reward stats when the Agent is disabled, because this will make // the rewards look lower than they actually are during shutdown. UpdateRewardStats(); } // The Agent is done, so we give it a new episode Id m_EpisodeId = EpisodeIdCounter.GetEpisodeId(); m_Reward = 0f; m_CumulativeReward = 0f; m_RequestAction = false; m_RequestDecision = false; } [Obsolete("GiveModel() has been deprecated, use SetModel() instead.")] public void GiveModel( string behaviorName, NNModel model, InferenceDevice inferenceDevice = InferenceDevice.CPU) { SetModel(behaviorName, model, inferenceDevice); } /// /// Updates the Model for the agent. Any model currently assigned to the /// agent will be replaced with the provided one. If the arguments are /// identical to the current parameters of the agent, the model will /// remain unchanged. /// /// The identifier of the behavior. This /// will categorize the agent when training. /// /// The model to use for inference. /// Define on what device the model /// will be run. public void SetModel( string behaviorName, NNModel model, InferenceDevice inferenceDevice = InferenceDevice.CPU) { if (behaviorName == m_PolicyFactory.behaviorName && model == m_PolicyFactory.model && inferenceDevice == m_PolicyFactory.inferenceDevice) { // If everything is the same, don't make any changes. return; } NotifyAgentDone(DoneReason.Disabled); m_PolicyFactory.model = model; m_PolicyFactory.inferenceDevice = inferenceDevice; m_PolicyFactory.behaviorName = behaviorName; ReloadPolicy(); } internal void ReloadPolicy() { if (!m_Initialized) { // If we haven't initialized yet, no need to make any changes now; they'll // happen in LazyInitialize later. return; } m_Brain?.Dispose(); m_Brain = m_PolicyFactory.GeneratePolicy(Heuristic); } /// /// Returns the current step counter (within the current episode). /// /// /// Current step count. /// public int StepCount { get { return m_StepCount; } } /// /// Overrides the current step reward of the agent and updates the episode /// reward accordingly. /// /// The new value of the reward. public void SetReward(float reward) { #if DEBUG Utilities.DebugCheckNanAndInfinity(reward, nameof(reward), nameof(SetReward)); #endif m_CumulativeReward += (reward - m_Reward); m_Reward = reward; } /// /// Increments the step and episode rewards by the provided value. /// /// Incremental reward value. public void AddReward(float increment) { #if DEBUG Utilities.DebugCheckNanAndInfinity(increment, nameof(increment), nameof(AddReward)); #endif m_Reward += increment; m_CumulativeReward += increment; } /// /// Retrieves the episode reward for the Agent. /// /// The episode reward. public float GetCumulativeReward() { return m_CumulativeReward; } void UpdateRewardStats() { var gaugeName = $"{m_PolicyFactory.behaviorName}.CumulativeReward"; TimerStack.Instance.SetGauge(gaugeName, GetCumulativeReward()); } [Obsolete("Done() has been deprecated, use EndEpisode() instead.")] public void Done() { EndEpisode(); } /// /// Sets the done flag to true. /// public void EndEpisode() { NotifyAgentDone(DoneReason.DoneCalled); _AgentReset(); } /// /// Is called when the agent must request the brain for a new decision. /// public void RequestDecision() { m_RequestDecision = true; RequestAction(); } /// /// Is called then the agent must perform a new action. /// public void RequestAction() { m_RequestAction = true; } /// Helper function that resets all the data structures associated with /// the agent. Typically used when the agent is being initialized or reset /// at the end of an episode. void ResetData() { var param = m_PolicyFactory.brainParameters; m_ActionMasker = new DiscreteActionMasker(param); // If we haven't initialized vectorActions, initialize to 0. This should only // happen during the creation of the Agent. In subsequent episodes, vectorAction // should stay the previous action before the Done(), so that it is properly recorded. if (m_Action.vectorActions == null) { m_Action.vectorActions = new float[param.numActions]; m_Info.storedVectorActions = new float[param.numActions]; } } [Obsolete("InitializeAgent() has been deprecated, use Initialize() instead.")] public virtual void InitializeAgent() { } /// /// Initializes the agent, called once when the agent is enabled. Can be /// left empty if there is no special, unique set-up behavior for the /// agent. /// /// /// One sample use is to store local references to other objects in the /// scene which would facilitate computing this agents observation. /// public virtual void Initialize() { #pragma warning disable 0618 InitializeAgent(); #pragma warning restore 0618 } /// /// When the Agent uses Heuristics, it will call this method every time it /// needs an action. This can be used for debugging or controlling the agent /// with keyboard. /// /// A float array corresponding to the next action of the Agent /// public virtual float[] Heuristic() { Debug.LogWarning("Heuristic method called but not implemented. Returning placeholder actions."); var param = m_PolicyFactory.brainParameters; return new float[param.numActions]; } /// /// Set up the list of ISensors on the Agent. By default, this will select any /// SensorBase's attached to the Agent. /// internal void InitializeSensors() { // Get all attached sensor components SensorComponent[] attachedSensorComponents; if (m_PolicyFactory.useChildSensors) { attachedSensorComponents = GetComponentsInChildren(); } else { attachedSensorComponents = GetComponents(); } sensors.Capacity += attachedSensorComponents.Length; foreach (var component in attachedSensorComponents) { sensors.Add(component.CreateSensor()); } // Support legacy CollectObservations var param = m_PolicyFactory.brainParameters; if (param.vectorObservationSize > 0) { collectObservationsSensor = new VectorSensor(param.vectorObservationSize); if (param.numStackedVectorObservations > 1) { var stackingSensor = new StackingSensor( collectObservationsSensor, param.numStackedVectorObservations); sensors.Add(stackingSensor); } else { sensors.Add(collectObservationsSensor); } } // Sort the Sensors by name to ensure determinism sensors.Sort((x, y) => x.GetName().CompareTo(y.GetName())); #if DEBUG // Make sure the names are actually unique for (var i = 0; i < sensors.Count - 1; i++) { Debug.Assert( !sensors[i].GetName().Equals(sensors[i + 1].GetName()), "Sensor names must be unique."); } #endif } /// /// Sends the Agent info to the linked Brain. /// void SendInfoToBrain() { if (!m_Initialized) { throw new UnityAgentsException("Call to SendInfoToBrain when Agent hasn't been initialized." + "Please ensure that you are calling 'base.OnEnable()' if you have overridden OnEnable."); } if (m_Brain == null) { return; } m_Info.storedVectorActions = m_Action.vectorActions; m_ActionMasker.ResetMask(); UpdateSensors(); using (TimerStack.Instance.Scoped("CollectObservations")) { CollectObservations(collectObservationsSensor); } using (TimerStack.Instance.Scoped("CollectDiscreteActionMasks")) { if (m_PolicyFactory.brainParameters.vectorActionSpaceType == SpaceType.Discrete) { CollectDiscreteActionMasks(m_ActionMasker); } } m_Info.discreteActionMasks = m_ActionMasker.GetMask(); m_Info.reward = m_Reward; m_Info.done = false; m_Info.maxStepReached = false; m_Info.episodeId = m_EpisodeId; m_Brain.RequestDecision(m_Info, sensors); // If we have any DemonstrationWriters, write the AgentInfo and sensors to them. foreach (var demoWriter in DemonstrationWriters) { demoWriter.Record(m_Info, sensors); } } void UpdateSensors() { foreach (var sensor in sensors) { sensor.Update(); } } /// /// Collects the vector observations of the agent. /// The agent observation describes the current environment from the /// perspective of the agent. /// /// /// The vector observations for the agent. /// /// /// An agents observation is any environment information that helps /// the Agent achieve its goal. For example, for a fighting Agent, its /// observation could include distances to friends or enemies, or the /// current level of ammunition at its disposal. /// Recall that an Agent may attach vector or visual observations. /// Vector observations are added by calling the provided helper methods /// on the VectorSensor input: /// - /// - /// - /// - /// - /// - /// - /// - /// Depending on your environment, any combination of these helpers can /// be used. They just need to be used in the exact same order each time /// this method is called and the resulting size of the vector observation /// needs to match the vectorObservationSize attribute of the linked Brain. /// Visual observations are implicitly added from the cameras attached to /// the Agent. /// public virtual void CollectObservations(VectorSensor sensor) { } /// /// Collects the masks for discrete actions. /// When using discrete actions, the agent will not perform the masked action. /// /// /// The action masker for the agent. /// /// /// When using Discrete Control, you can prevent the Agent from using a certain /// action by masking it with /// public virtual void CollectDiscreteActionMasks(DiscreteActionMasker actionMasker) { } [Obsolete("AgentAction() has been deprecated, use OnActionReceived() instead.")] public virtual void AgentAction(float[] vectorAction) { } /// /// Specifies the agent behavior at every step based on the provided /// action. /// /// /// Vector action. Note that for discrete actions, the provided array /// will be of length 1. /// public virtual void OnActionReceived(float[] vectorAction) { #pragma warning disable 0618 AgentAction(m_Action.vectorActions); #pragma warning restore 0618 } [Obsolete("AgentReset() has been deprecated, use OnEpisodeBegin() instead.")] public virtual void AgentReset() { } /// /// Specifies the agent behavior when being reset, which can be due to /// the agent or Academy being done (i.e. completion of local or global /// episode). /// public virtual void OnEpisodeBegin() { #pragma warning disable 0618 AgentReset(); #pragma warning restore 0618 } /// /// Returns the last action that was decided on by the Agent /// /// /// The last action that was decided by the Agent (or null if no decision has been made) /// public float[] GetAction() { return m_Action.vectorActions; } /// /// An internal reset method that updates internal data structures in /// addition to calling . /// void _AgentReset() { ResetData(); m_StepCount = 0; OnEpisodeBegin(); } /// /// Scales continuous action from [-1, 1] to arbitrary range. /// /// /// /// /// protected static float ScaleAction(float rawAction, float min, float max) { var middle = (min + max) / 2; var range = (max - min) / 2; return rawAction * range + middle; } /// /// Signals the agent that it must sent its decision to the brain. /// void SendInfo() { // If the Agent is done, it has just reset and thus requires a new decision if (m_RequestDecision) { SendInfoToBrain(); m_Reward = 0f; m_RequestDecision = false; } } void AgentIncrementStep() { m_StepCount += 1; } /// Used by the brain to make the agent perform a step. void AgentStep() { if ((m_RequestAction) && (m_Brain != null)) { m_RequestAction = false; OnActionReceived(m_Action.vectorActions); } if ((m_StepCount >= maxStep) && (maxStep > 0)) { NotifyAgentDone(DoneReason.MaxStepReached); _AgentReset(); } } void DecideAction() { m_Action.vectorActions = m_Brain?.DecideAction(); if (m_Action.vectorActions == null) { ResetData(); } } } }