1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
//===--- DifferentiationUtilities.swift -----------------------*- swift -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// Utilities for creating differentiable functions, debugging, and customizing
// derivatives.
//
//===----------------------------------------------------------------------===//
import Swift
//===----------------------------------------------------------------------===//
// Derivative customization
//===----------------------------------------------------------------------===//
/// Returns `x` like an identity function. When used in a context where `x` is
/// being differentiated with respect to, this function will not produce any
/// derivative at `x`.
@inlinable
@inline(__always)
@_semantics("autodiff.nonvarying")
public func withoutDerivative<T>(at x: T) -> T {
x
}
//===----------------------------------------------------------------------===//
// Diagnostics
//===----------------------------------------------------------------------===//
@_silgen_name("_fatalErrorForwardModeDifferentiationDisabled")
public func _fatalErrorForwardModeDifferentiationDisabled() -> Never {
fatalError("""
JVP does not exist. Use \
'-Xfrontend -enable-experimental-forward-mode-differentiation' to enable \
differential-first differentiation APIs.
""")
}
|
