---

yaml
---
r: 340967
b: refs/heads/rxwei-patch-1
c: 925c768
h: refs/heads/master
i:
  340965: 3cc1868
  340963: cc112c8
  340959: 900c641

Author: dan-zheng

[refs]

@@ -1015,7 +1015,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2018-08-18-a: b10b1fce14385faa6d44f6b933e95
 refs/heads/rdar-43033749-fix-batch-mode-no-diags-swift-5.0-branch: a14e64eaad30de89f0f5f0b2a782eed7ecdcb255
 refs/heads/revert-19006-error-bridging-integer-type: 8a9065a3696535305ea53fe9b71f91cbe6702019
 refs/heads/revert-19050-revert-19006-error-bridging-integer-type: ecf752d54b05dd0a20f510f0bfa54a3fec3bcaca
-refs/heads/rxwei-patch-1: 8dac116bdcf115e47765b252395cd5eb8c7cf999
+refs/heads/rxwei-patch-1: 925c7685d4ed1a395bb286de6784846478471d0a
 refs/heads/shahmishal-patch-1: e58ec0f7488258d42bef51bc3e6d7b3dc74d7b2a
 refs/heads/typelist-existential: 4046359efd541fb5c72d69a92eefc0a784df8f5e
 refs/tags/swift-4.2-DEVELOPMENT-SNAPSHOT-2018-08-20-a: 4319ba09e4fb8650ee86061075c74a016b6baab9

branches/rxwei-patch-1/stdlib/public/core/AutoDiff.swift

@@ -248,13 +248,13 @@ public func differentiableFunction<T, U, R>(
 }
 
 public extension Differentiable {
-  @differentiable(wrt: self, vjp: _vjpWithGrad)
-  func withGradient(_ body: @escaping (inout TangentVector) -> Void) -> Self {
+  @differentiable(wrt: self, vjp: _vjpWithDerivative)
+  func withDerivative(_ body: @escaping (inout TangentVector) -> Void) -> Self {
     return self
   }
 
   @inlinable
-  internal func _vjpWithGrad(
+  internal func _vjpWithDerivative(
     _ body: @escaping (inout TangentVector) -> Void
   ) -> (Self, (TangentVector) -> TangentVector) {
     return (self, { grad in
@@ -263,21 +263,6 @@ public extension Differentiable {
       return grad
     })
   }
-
-  @differentiable(wrt: self, vjp: _vjpWithGrad)
-  func withGradient(_ body: @escaping (TangentVector) -> Void) -> Self {
-    return self
-  }
-
-  @inlinable
-  internal func _vjpWithGrad(
-    _ body: @escaping (TangentVector) -> Void
-  ) -> (Self, (TangentVector) -> TangentVector) {
-    return (self, { grad in
-      body(grad)
-      return grad
-    })
-  }
 }
 
 /// Make a function be recomputed in its pullback, known as "checkpointing" in

branches/rxwei-patch-1/test/AutoDiff/custom_derivatives.swift

@@ -72,18 +72,18 @@ CustomDerivativesTests.test("Checkpointing") {
 
 CustomDerivativesTests.test("SumOfGradPieces") {
   var grad: Float = 0
-  let addToGrad = { grad += $0 }
+  func addToGrad(_ x: inout Float) { grad += x }
   _ = gradient(at: 4) { (x: Float) in
-    x.withGradient(addToGrad)
-      * x.withGradient(addToGrad)
-        * x.withGradient(addToGrad)
+    x.withDerivative(addToGrad)
+      * x.withDerivative(addToGrad)
+        * x.withDerivative(addToGrad)
   }
   expectEqual(48, grad)
 }
 
 CustomDerivativesTests.test("ModifyGradientOfSum") {
   expectEqual(30, gradient(at: 4) { (x: Float) in
-    x.withGradient { $0 *= 10 } + x.withGradient { $0 *= 20 }
+    x.withDerivative { $0 *= 10 } + x.withDerivative { $0 *= 20 }
   })
 }