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constructRowMajor operates over a pair of ranges.

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This commit is contained in:
Rob Rix 2015-11-05 15:45:19 -05:00
parent 3f5812bef5
commit 38686fee20
1 changed files with 5 additions and 5 deletions
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10
prototype/Doubt/Matrix.swift
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@ -5,7 +5,7 @@
/// Values are retrieved by subscripting with row/column indices. Out-of-bound indices produce `nil` values, rather than asserting.
public struct Matrix<A> {
public init(width: Int, height: Int, compute: (Int, Int) -> A) {
self.init(width: width, height: height, values: constructRowMajor(width, height: height, forEach: { i, j in Memo { compute(i, j) } }))
self.init(width: width, height: height, values: constructRowMajor(0..<width, down: 0..<height, forEach: { i, j in Memo { compute(i, j) } }))
}
public let width: Int
@ -36,11 +36,11 @@ public struct Matrix<A> {
}
/// Constructs a row-major ordering of values produced with `forEach`.
private func constructRowMajor<A>(width: Int, height: Int, @noescape forEach: (Int, Int) -> A) -> [A] {
private func constructRowMajor<A, I: ForwardIndexType>(across: Range<I>, down: Range<I>, @noescape forEach: (I, I) -> A) -> [A] {
var values: [A] = []
values.reserveCapacity(width * height)
for j in 0..<height {
for i in 0..<width {
values.reserveCapacity(Int(across.count.toIntMax()) * Int(down.count.toIntMax()))
for j in across {
for i in down {
values.append(forEach(i, j))
}
}