marcrasi

Compile Time Constant Expressions for Swift

• Proposal: SE-NNNN
• Authors: Marc Rasi, Chris Lattner
• Review Manager: TBD
• Status: Awaiting implementation

Swift-evolution thread: https://forums.swift.org/t/pitch-compile-time-constant-expressions-for-swift/12879

Introduction

marcrasi

protocol Proto {
  @differentiable(reverse)
  func f(_ x: Float) -> Float
}

func callF<T: Proto>(_ t: T, _ x: Float) -> Float {
  return t.f(x)
}

func gradFWrtX<T: Proto>(_ t: T, at x: Float) -> Float {

marcrasi

sil_stage canonical

import Builtin
import Swift
import SwiftShims

protocol Proto {
  @differentiable(reverse)
  func f(_ x: Float) -> Float
}

marcrasi

[1/33] Performing build step for 'libdispatch'
ninja: no work to do.
[2/27] Compiling /usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux-x86_64/stdlib/public/core/linux/x86_64/Swift.o
FAILED: stdlib/public/core/linux/x86_64/Swift.o 
cd /usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux-x86_64/stdlib/public/core && /usr/bin/python /usr/local/google/home/marcrasi/swift-base/swift/utils/line-directive @/usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux-x86_64/stdlib/public/core/OdCaQ.txt -- /usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux-x86_64/./bin/swiftc -c -sdk / -target x86_64-unknown-linux-gnu -resource-dir /usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux-x86_64/./lib/swift -O -I /usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux-x86_64/./lib/swift/linux/x86_64 -module-cache-path /usr/local/google/home/marcrasi/swift-base/build/buildbot_linux/swift-linux

marcrasi

# -*- coding: utf-8 -*-
"""split_into_batches_oom.ipynb

Automatically generated by Colaboratory.

Original file is located at
    https://colab.research.google.com/drive/1UWb-URpxZgdkTICBZlxGWfJr7U35uvJk
"""

# %enableCompletion

marcrasi

import TensorFlow

struct ConvBN: Layer {
    var conv: Conv2D<Float>
    var norm: BatchNorm<Float>

    public init(filterShape: (Int, Int, Int, Int), strides: (Int, Int) = (1, 1),
        padding: Padding, learningPhaseIndicator: LearningPhaseIndicator) {
        self.conv = Conv2D(
            filterShape: filterShape, strides: strides, padding: padding)

marcrasi

First the package needs a dynamic library product. You might have to modify the package to have one. Here's an example.

Now make a notebook that clones the package, builds the package, and copies the build artifacts into the right places. Here's an example.

In a Swift notebook, dlopen the shared library and then import the module. For example:

import Glibc
dlopen("/swift/toolchain/usr/lib/swift/linux/libDeckOfPlayingCards.so", RTLD_NOW)
import DeckOfPlayingCards

marcrasi

public struct ProductSpaceVector<Element> {
  public var elements: [Element]
  public init(_ elements: [Element]) { self.elements = elements }
}

extension ProductSpaceVector : Equatable where Element : Equatable {
  public static func == (lhs: ProductSpaceVector, rhs: ProductSpaceVector) -> Bool {
    return lhs.elements == rhs.elements
  }
}

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public struct ProductSpaceVector<Element> {
  public var elements: [Element]
  public init(_ elements: [Element]) { self.elements = elements }
}

extension ProductSpaceVector : Equatable where Element : Equatable {
  public static func == (lhs: ProductSpaceVector, rhs: ProductSpaceVector) -> Bool {
    return lhs.elements == rhs.elements
  }
}

marcrasi

extension Array where Element: Differentiable {
    /// Views the array as the differentiable product manifold of `Element` with itself `count` times.
    public struct DifferentiableView: Differentiable {
        /// The array that we are viewing.
        public var base: [Element]

        /// Construct a view of the given array.
        public init(_ base: [Element]) { self.base = base }
        
        // MARK: - Differentiable conformance.