Introduced Angle type [Issue apple#88]

Sources/RealModule/Angle.swift

@@ -0,0 +1,92 @@
+//===--- Angle.swift ------------------------------------------*- swift -*-===//
+//
+// This source file is part of the Swift Numerics open source project
+//
+// Copyright (c) 2020 Apple Inc. and the Swift Numerics 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
+//
+//===----------------------------------------------------------------------===//
+
+/// A wrapper type for angle operations and functions
+///
+/// All trigonometric functions expect the argument to be passed as radians (Real), but this is not enforced by the type system.
+/// This type serves exactly this purpose, and can be seen as an alternative to the underlying Real implementation.
+public struct Angle<T: Real> {
+    public var radians: T
+    public init(radians: T) { self.radians = radians }
+    public static func radians(_ val: T) -> Angle<T> { .init(radians: val) }
+
+    public var degrees: T { radians * 180 / .pi }
+    public init(degrees: T) { self.init(radians: degrees * .pi / 180) }
+    public static func degrees(_ val: T) -> Angle<T> { .init(degrees: val) }
+}
+
+public extension Angle {
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.cosh()`
+    var cosh: T { T.cosh(radians) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.sinh()`
+    var sinh: T { T.sinh(radians) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.tanh()`
+    var tanh: T { T.tanh(radians) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.cos()`
+    var cos: T { T.cos(radians) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.sin()`
+    var sin: T { T.sin(radians) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.tan()`
+    var tan: T { T.tan(radians) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.acosh()`
+    static func acosh(_ x: T) -> Self { Angle.radians(T.acosh(x)) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.asinh()`
+    static func asinh(_ x: T) -> Self { Angle.radians(T.asinh(x)) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.atanh()`
+    static func atanh(_ x: T) -> Self { Angle.radians(T.atanh(x)) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.acos()`
+    static func acos(_ x: T) -> Self { Angle.radians(T.acos(x)) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.asin()`
+    static func asin(_ x: T) -> Self { Angle.radians(T.asin(x)) }
+
+    /// See also:
+    /// -
+    /// `ElementaryFunctions.atan()`
+    static func atan(_ x: T) -> Self { Angle.radians(T.atan(x)) }
+
+    /// See also:
+    /// -
+    /// `RealFunctions.atan2()`
+    static func atan2(y: T, x: T) -> Self { Angle.radians(T.atan2(y: y, x: x)) }
+}

Tests/RealTests/AngleTests.swift

@@ -0,0 +1,80 @@
+//===--- AngleTests.swift -------------------------------------*- swift -*-===//
+//
+// This source file is part of the Swift Numerics open source project
+//
+// Copyright (c) 2020 Apple Inc. and the Swift Numerics 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
+//
+//===----------------------------------------------------------------------===//
+
+import RealModule
+import XCTest
+import _TestSupport
+
+internal extension Real
+where Self: BinaryFloatingPoint {
+    static func conversionBetweenRadiansAndDegreesChecks() {
+        let angleFromRadians = Angle<Self>(radians: Self.pi / 3)
+        assertClose(60, angleFromRadians.degrees)
+
+        let angleFromDegrees = Angle<Self>(degrees: 120)
+        // the compiler complains with the following line
+        // assertClose(2 * Self.pi / 3, angleFromDegrees.radians)
+        assertClose(2 * Double(Self.pi) / 3, angleFromDegrees.radians)
+    }
+
+    static func trigonometricFunctionChecks() {
+        assertClose(1.1863995522992575361931268186727044683, Angle<Self>.acos(0.375).radians)
+        assertClose(0.3843967744956390830381948729670469737, Angle<Self>.asin(0.375).radians)
+        assertClose(0.3587706702705722203959200639264604997, Angle<Self>.atan(0.375).radians)
+        assertClose(0.54041950027058415544357836460859991,   Angle<Self>.atan2(y: 0.375, x: 0.625).radians)
+
+        assertClose(0.9305076219123142911494767922295555080, Angle<Self>(radians: 0.375).cos)
+        assertClose(0.3662725290860475613729093517162641571, Angle<Self>(radians: 0.375).sin)
+        assertClose(0.3936265759256327582294137871012180981, Angle<Self>(radians: 0.375).tan)
+    }
+
+    static func hyperbolicTrigonometricFunctionChecks() {
+        assertClose(0.4949329230945269058895630995767185785, Angle<Self>.acosh(1.125).radians)
+        assertClose(0.9670596312833237113713762009167286709, Angle<Self>.asinh(1.125).radians)
+        assertClose(0.7331685343967135223291211023213964500, Angle<Self>.atanh(0.625).radians)
+        assertClose(1.0711403467045867672994980155670160493, Angle<Self>(radians: 0.375).cosh)
+        assertClose(0.3838510679136145687542956764205024589, Angle<Self>(radians: 0.375).sinh)
+        assertClose(0.3583573983507859463193602315531580424, Angle<Self>(radians: 0.375).tanh)
+    }
+}
+
+final class AngleTests: XCTestCase {
+    #if swift(>=5.3) && !(os(macOS) || os(iOS) && targetEnvironment(macCatalyst))
+    func testFloat16() {
+        if #available(iOS 14.0, watchOS 14.0, tvOS 7.0, *) {
+            Float16.conversionBetweenRadiansAndDegreesChecks()
+            Float16.trigonometricFunctionChecks()
+            Float16.hyperbolicTrigonometricFunctionChecks()
+        }
+    }
+    #endif
+
+    func testFloat() {
+        Float.conversionBetweenRadiansAndDegreesChecks()
+        Float.trigonometricFunctionChecks()
+        Float.hyperbolicTrigonometricFunctionChecks()
+    }
+
+    func testDouble() {
+        Double.conversionBetweenRadiansAndDegreesChecks()
+        Double.trigonometricFunctionChecks()
+        Double.hyperbolicTrigonometricFunctionChecks()
+    }
+
+    #if (arch(i386) || arch(x86_64)) && !os(Windows) && !os(Android)
+    func testFloat80() {
+        Float80.conversionBetweenRadiansAndDegreesChecks()
+        Float80.trigonometricFunctionChecks()
+        Float80.hyperbolicTrigonometricFunctionChecks()
+    }
+    #endif
+}