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ߦྻΛSwiftͰ࣮͢Δ
USAMI Kosuke
Fenrir Inc.
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ࣗݾհ
• Ӊࠤݟެี
• ϑΣϯϦϧגࣜձࣾ
• iOS ΞϓϦ։ൃ : Swift / C#
• ֶੜֶ࣌ઐ߈
• ࠷ۙɺ·ͨগ͠ਅ໘ʹΓͩͨ͠
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ߦྻͱ
• ͜͜Ͱ͍͏ߦྻɺઢܕͰग़ͯ͘ΔߦྻʢMatrixʣͷ͜ͱ
• ػցֶशͳͲͰΘΕΔ͜ͱ͔Βɺ࠷ۙগ͠͞ΕͯΔ͔
͠Εͳ͍ʁ ΒΜ͚Ͳɻ
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ߦྻΛ Swift Ͱ࣮ͯ͠ΈΔ
• ֶͷ֓೦ΛϓϩάϥϛϯάݴޠͰදݱ͢Δతɿ
• ֶͷ֓೦Λཧղ͍ͨ͠
• ϓϩάϥϛϯάݴޠΛཧղ͍ͨ͠
• ࠓճ࣮༻͋·Γॏࢹ͠ͳ͍
• طʹ Swift for TensorFlow ͳͲ͕͋Δ
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ԿΛ࣮͢Δ͔
• ࠓճɺߦྻͷԋࢉʹணͨ͠
• ͠ࢉ / εΧϥʔഒ / ͔͚ࢉ
• ߦྻʹɺϕΫτϧΛϕΫτϧʹҠ͢ઢܕࣸ૾Λදݱ͢Δͱ͍
͏ॏཁͳҙຯ͕͋Δ͕ɺࠓճѻΘͳ͍ʢͦΕʹϕΫτϧ
࣮͢Δඞཁ͕͋ΔͷͰɾɾɾʣ
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ߦྻΛදݱ͢ΔͨΊͷσʔλ
• ֤ͷܕԿ͔
• Կߦ͋Δ͔ / Կྻ͋Δ͔
• XߦYྻͷΛऔಘ͢Δ / ઃఆ͢Δ
• ߦϕΫτϧ / ྻϕΫτϧ
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Matrix ϓϩτίϧ
protocol MatrixProtocol {
associatedtype Scalar: Numeric
var rows: Int { get }
var columns: Int { get }
subscript(row: Int, column: Int) -> Scalar { get set }
func vector(row: Int) -> [Scalar]
func vector(column: Int) -> [Scalar]
}
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ॳظԽ (1)
struct Matrix : MatrixProtocol {
typealias Scalar = Float
private var grid: [Scalar]
init(rows: Int, columns: Int, grid: [Scalar]) {
self.rows = rows
self.columns = columns
self.grid = grid
}
}
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ॳظԽ (2)
// ͬͺΓɺ͜͏ॻ͖͍ͨΑͶ
let a = Matrix(elements: [[1, 2], [3, 4]])
struct Matrix {
init(elements: [[Scalar]]) {
let rows = elements.count
let columns = elements.first?.count ?? 0
let grid = elements.flatMap { $0 }
self.init(rows: rows, columns: columns, grid: grid)
}
}
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ͷऔಘͱઃఆ
struct Matrix : MatrixProtocol {
subscript(row: Int, column: Int) -> Scalar {
get {
return grid[row * columns + column]
}
set {
grid[row * columns + column] = newValue
}
}
}
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ߦϕΫτϧ / ྻϕΫτϧ
struct Matrix : MatrixProtocol {
func vector(row: Int) -> [Scalar] {
return (0.. [Scalar] {
return (0..
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ԋࢉͷ࣮
• ߦྻͷԋࢉ
• ͠ࢉ / εΧϥʔഒ / ͔͚ࢉ
• ͜ΕΒΛఆٛ͢Δϓϩτίϧ͕طʹ͋ΔͳΒ४ڌ͍ͤͨ͞
• ඪ४ͷ API ʹͳΔ͋͘Θ͍ͤͨ
• ͳ͍߹ͰɺϓϩτίϧΛఆٛͯ͠४ڌͤ͞ΔΑ͏ʹ͢Δ
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͠ࢉͷϓϩτίϧ
• AdditiveArithmetic ϓϩτίϧΛ͏
• Swift 5 ͷ AdditiveArithmetic protocol ͱԿ͔
ͱ͍͏هࣄΛҎલ Qiita ʹॻ͍ͨ
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͠ࢉͷ࣮
extension Matrix : AdditiveArithmetic {
static func + (lhs: Matrix, rhs: Matrix) -> Matrix {
return Matrix(
rows: lhs.rows, columns: lhs.columns,
grid: zip(lhs.grid, rhs.grid).map(+))
}
static func - (lhs: Matrix, rhs: Matrix) -> Matrix {
return Matrix(
rows: lhs.rows, columns: lhs.columns,
grid: zip(lhs.grid, rhs.grid).map(-))
}
}
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՝ : zero Ͳ͏͢Δʁ
protocol AdditiveArithmetic {
static var zero: Self
}
• ͯ͢ͷ͕ 0 ͷߦྻ͕θϩߦྻͰ͋Δͷ͕ͩɾɾɾ
• ߦྻͷαΠζʹΑͬͯมΘΔͷͰɺstatic Ͱఆٛͮ͠Β͍
• ݱࡏɺྑ͍ղܾ͕ͳ͍ɾɾɾ
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εΧϥʔഒͷϓϩτίϧͷఆٛ
• Swift for TensorFlow ʹ͋ΔͷͰͦͷ··ਅࣅ͢Δ
protocol VectorNumeric {
associatedtype Scalar: Numeric
static func * (lhs: Scalar, rhs: Self) -> Self
static func *= (lhs: inout Self, rhs: Scalar)
}
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εΧϥʔഒͷ࣮
extension Matrix : VectorNumeric {
static func * (lhs: Scalar, rhs: Matrix) -> Matrix {
return Matrix(
rows: rhs.rows, columns: rhs.columns,
grid: rhs.grid.map { lhs * $0 })
}
}
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͔͚ࢉͷϓϩτίϧ
• Swift ඪ४ͷ Numeric ͰͲ͏͔ʁ ҎԼͷϓϩύςΟ͕
protocol Numeric {
associatedtype Magnitude : Comparable, Numeric
var magnitude: Self.Magnitude { get }
}
• magnitude ઈରΛฦ͢ɾɾɾߦྻʹͳ͍֓೦
• ͕ͨͬͯ͠ɺߦྻ Numeric ͡Όͳ͍
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͔͚ࢉͷϓϩτίϧͷఆٛ
• Numeric ͔Β magnitude Λͣ͢
protocol MultiplicativeArithmetic {
static func * (lhs: Self, rhs: Self) -> Self
static func *= (lhs: inout Self, rhs: Self)
}
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͔͚ࢉͷ࣮
extension Matrix : MultiplicativeArithmetic {
static func * (lhs: Matrix, rhs: Matrix) -> Matrix {
return Matrix(
rows: lhs.rows, columns: rhs.columns,
grid: (0..
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ࠓޙͷ՝
• associatedtype ΑΓδΣωϦΫεͷ΄͏͕ྑ͍͔ʁ
• ͬͺΓ Numeric ʹ͍͕ͨ͠ʁ
• magnitude ߦྻ͕ࣜߟ͑ΒΕΔ͕ਖ਼ํߦྻͷΈ
• ߦྻΛϕΫτϧʹ࡞༻͍ͤͨ͞
• ͜ͷߦྻΛ͢ΔΑ͏ʹϕΫτϧΛఆٛͯ͠Δ