Track reward for inference (#3320)

* WIP

* add reward stats

* const, dont write timers on mobile

Project/.gitignore

 /Assets/AssetStoreTools*
 /Assets/Plugins*
 /Assets/Demonstrations*
+/Assets/ML-Agents/Timers*
 /csharp_timers.json
 
 # Environemnt logfile

com.unity.ml-agents/Runtime/Agent.cs

             // 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);
+
+            UpdateRewardStats();
+
             // The Agent is done, so we give it a new episode Id
             m_EpisodeId = EpisodeIdCounter.GetEpisodeId();
             m_Reward = 0f;
         public float GetCumulativeReward()
         {
             return m_CumulativeReward;
+        }
+
+        void UpdateRewardStats()
+        {
+            var gaugeName = $"{m_PolicyFactory.behaviorName}.CumulativeReward";
+            TimerStack.Instance.SetGauge(gaugeName, GetCumulativeReward());
         }
 
         /// <summary>

com.unity.ml-agents/Runtime/Timer.cs

 using UnityEngine.Profiling;
 using System.Runtime.Serialization;
 using System.Runtime.Serialization.Json;
+using UnityEngine.SceneManagement;
 
 namespace MLAgents
 {
     [DataContract]
     public class GaugeNode
     {
+        const float k_SmoothingFactor = .25f; // weight for exponential moving average.
+
         [DataMember]
         public float value;
         [DataMember(Name = "min")]
+        [DataMember(Name = "weightedAverage")]
+        public float weightedAverage;
+            weightedAverage = value;
             minValue = value;
             maxValue = value;
             count = 1;
         {
             minValue = Mathf.Min(minValue, newValue);
             maxValue = Mathf.Max(maxValue, newValue);
+            // update exponential moving average
+            weightedAverage = (k_SmoothingFactor * newValue) + ((1f - k_SmoothingFactor) * weightedAverage);
             value = newValue;
             ++count;
         }
         /// <param name="filename"></param>
         public void SaveJsonTimers(string filename = null)
         {
-            if (filename == null)
+# if UNITY_EDITOR || UNITY_STANDALONE_WIN || UNITY_STANDALONE_OSX || UNITY_STANDALONE_LINUX
+            try
-                var fullpath = Path.GetFullPath(".");
-                filename = $"{fullpath}/csharp_timers.json";
+                if (filename == null)
+                {
+                    var activeScene = SceneManager.GetActiveScene();
+                    var timerDir = Path.Combine(Application.dataPath, "ML-Agents", "Timers");
+                    Directory.CreateDirectory(timerDir);
+
+                    filename = Path.Combine(timerDir, $"{activeScene.name}_timers.json");
+                }
+
+                var fs = new FileStream(filename, FileMode.Create, FileAccess.Write);
+                SaveJsonTimers(fs);
+                fs.Close();
-            var fs = new FileStream(filename, FileMode.Create, FileAccess.Write);
-            SaveJsonTimers(fs);
-            fs.Close();
+            catch (IOException)
+            {
+                // It's possible we don't have write access to the directory.
+                Debug.LogWarning($"Unable to save timers to file {filename}");
+            }
+#endif
         }
 
         /// <summary>