Added closure-based initializer function for Matrix and corresponding unit test

regexident · regexident · commit e96bf943e341 · 2019-10-02T01:29:12.000+02:00
diff --git a/Sources/Surge/Linear Algebra/Vector.swift b/Sources/Surge/Linear Algebra/Vector.swift
@@ -46,6 +46,17 @@ public struct Vector<Scalar> where Scalar: FloatingPoint, Scalar: ExpressibleByF
         self.dimensions = scalars.count
         self.scalars = scalars
     }
+
+    public init(dimensions: Int, _ closure: (Int) throws -> Scalar) rethrows {
+        var scalars: [Scalar] = []
+        scalars.reserveCapacity(dimensions)
+
+        for index in 0..<dimensions {
+            scalars.append(try closure(index))
+        }
+
+        self.init(scalars)
+    }
 }
 
 // MARK: - ExpressibleByArrayLiteral
diff --git a/Tests/SurgeTests/VectorTests.swift b/Tests/SurgeTests/VectorTests.swift
@@ -27,6 +27,19 @@ import XCTest
 class VectorTests: XCTestCase {
     // MARK: - Initialization
 
+    func test_init_dimensions_repeatedValue() {
+        typealias Scalar = Double
+
+        let dimensions = 5
+        let repeatedValue: Scalar = 42
+
+        let actual: Vector<Scalar> = Vector(dimensions: dimensions, repeatedValue: repeatedValue)
+
+        let expected: Vector<Scalar> = [42, 42, 42, 42, 42]
+
+        XCTAssertEqual(actual, expected)
+    }
+
     func test_init() {
         typealias Scalar = Double
 
@@ -36,6 +49,17 @@ class VectorTests: XCTestCase {
         XCTAssertEqual(lhs.scalars, values)
     }
 
+    func test_init_dimensions_closure() {
+        typealias Scalar = Double
+
+        let dimensions = 5
+        let actual: Vector<Scalar> = Vector(dimensions: dimensions) { Scalar($0)
+        }
+        let expected: Vector<Scalar> = [0, 1, 2, 3, 4]
+
+        XCTAssertEqual(actual, expected)
+    }
+
     // MARK: - Subscript
 
     func test_subscript() {
