From 209db0f07ad54cf78a482c33d8335ef382588a4f Mon Sep 17 00:00:00 2001
From: Chris Elion <chris.elion@unity3d.com>
Date: Mon, 22 Mar 2021 15:37:04 -0700
Subject: [PATCH] change default barracuda behavior

---
 com.unity.ml-agents/CHANGELOG.md                      |  3 +++
 com.unity.ml-agents/Runtime/Agent.cs                  |  2 +-
 com.unity.ml-agents/Runtime/Inference/ModelRunner.cs  |  1 +
 .../Runtime/Policies/BarracudaPolicy.cs               | 11 ++++++++---
 .../Runtime/Policies/BehaviorParameters.cs            |  2 +-
 5 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/com.unity.ml-agents/CHANGELOG.md b/com.unity.ml-agents/CHANGELOG.md
index fb05f310cf..bd9531e799 100755
--- a/com.unity.ml-agents/CHANGELOG.md
+++ b/com.unity.ml-agents/CHANGELOG.md
@@ -32,6 +32,9 @@ interface was removed. (#5164)
 - Added ML-Agents package settings. (#5027)
 - Make com.unity.modules.unityanalytics an optional dependency. (#5109)
 - Make com.unity.modules.physics and com.unity.modules.physics2d optional dependencies. (#5112)
+- The default `InferenceDevice` is now `InferenceDevice.Default`, which is equivalent to `InferenceDevice.Burst`. If you
+depend on the previous behavior, you can explicitly set the Agent's `InferenceDevice` to `InferenceDevice.CPU`. (#5175)
+
 #### ml-agents / ml-agents-envs / gym-unity (Python)
 
 ### Bug Fixes
diff --git a/com.unity.ml-agents/Runtime/Agent.cs b/com.unity.ml-agents/Runtime/Agent.cs
index 5c7cc73488..580e1571c3 100644
--- a/com.unity.ml-agents/Runtime/Agent.cs
+++ b/com.unity.ml-agents/Runtime/Agent.cs
@@ -617,7 +617,7 @@ void NotifyAgentDone(DoneReason doneReason)
         public void SetModel(
             string behaviorName,
             NNModel model,
-            InferenceDevice inferenceDevice = InferenceDevice.CPU)
+            InferenceDevice inferenceDevice = InferenceDevice.Default)
         {
             if (behaviorName == m_PolicyFactory.BehaviorName &&
                 model == m_PolicyFactory.Model &&
diff --git a/com.unity.ml-agents/Runtime/Inference/ModelRunner.cs b/com.unity.ml-agents/Runtime/Inference/ModelRunner.cs
index 12a8188c52..054ac2ac4e 100644
--- a/com.unity.ml-agents/Runtime/Inference/ModelRunner.cs
+++ b/com.unity.ml-agents/Runtime/Inference/ModelRunner.cs
@@ -83,6 +83,7 @@ public ModelRunner(
                     case InferenceDevice.Burst:
                         executionDevice = WorkerFactory.Type.CSharpBurst;
                         break;
+                    case InferenceDevice.Default: // fallthrough
                     default:
                         executionDevice = WorkerFactory.Type.CSharpBurst;
                         break;
diff --git a/com.unity.ml-agents/Runtime/Policies/BarracudaPolicy.cs b/com.unity.ml-agents/Runtime/Policies/BarracudaPolicy.cs
index c9a1202af5..5e76084b20 100644
--- a/com.unity.ml-agents/Runtime/Policies/BarracudaPolicy.cs
+++ b/com.unity.ml-agents/Runtime/Policies/BarracudaPolicy.cs
@@ -13,10 +13,9 @@ namespace Unity.MLAgents.Policies
     public enum InferenceDevice
     {
         /// <summary>
-        /// CPU inference. Corresponds to in WorkerFactory.Type.CSharp Barracuda.
-        /// Burst is recommended instead; this is kept for legacy compatibility.
+        /// Default inference. This is currently the same as Burst, but may change in the future.
         /// </summary>
-        CPU = 0,
+        Default = 0,
 
         /// <summary>
         /// GPU inference. Corresponds to WorkerFactory.Type.ComputePrecompiled in Barracuda.
@@ -27,6 +26,12 @@ public enum InferenceDevice
         /// CPU inference using Burst. Corresponds to WorkerFactory.Type.CSharpBurst in Barracuda.
         /// </summary>
         Burst = 2,
+
+        /// <summary>
+        /// CPU inference. Corresponds to in WorkerFactory.Type.CSharp Barracuda.
+        /// Burst is recommended instead; this is kept for legacy compatibility.
+        /// </summary>
+        CPU = 3,
     }
 
     /// <summary>
diff --git a/com.unity.ml-agents/Runtime/Policies/BehaviorParameters.cs b/com.unity.ml-agents/Runtime/Policies/BehaviorParameters.cs
index 33a9089d75..ae05284d50 100644
--- a/com.unity.ml-agents/Runtime/Policies/BehaviorParameters.cs
+++ b/com.unity.ml-agents/Runtime/Policies/BehaviorParameters.cs
@@ -109,7 +109,7 @@ public NNModel Model
         }
 
         [HideInInspector, SerializeField]
-        InferenceDevice m_InferenceDevice = InferenceDevice.Burst;
+        InferenceDevice m_InferenceDevice = InferenceDevice.Default;
 
         /// <summary>
         /// How inference is performed for this Agent's model.