From 541e7c38ef1e71c325f2567067c589f07ecaf2e3 Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Sun, 1 Nov 2015 20:40:27 -0800
Subject: [PATCH] [Math] Move the multiplication to the * operator

*= must be done with a temporary variable first to avoid stepping on the other elements.
---
 Math/Math/Matrix.swift | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/Math/Math/Matrix.swift b/Math/Math/Matrix.swift
index 7339cbd..d4c3ea6 100644
--- a/Math/Math/Matrix.swift
+++ b/Math/Math/Matrix.swift
@@ -270,19 +270,22 @@ public func -<T: Matrix>(lhs: T, rhs: T) -> T {
 // MARK: Matrix-Matrix multiplication
 
 public func *=<T: Matrix>(inout lhs: T, rhs: T) {
-    for i in 0..<T.dimension {
-        for j in 0..<T.dimension {
-            // Each cell is Sigma(k=0, M)(lhs[ik] * rhs[kj]
-            for k in 0..<T.dimension {
-                lhs[i,j] += lhs[i,k] * rhs[k,j]
-            }
-        }
+    let result = lhs * rhs
+    for i in 0..<T.count {
+        lhs[i] = result[i]
     }
 }
 
 public func *<T: Matrix>(lhs: T, rhs: T) -> T {
-    var out = lhs
-    out *= rhs
+    var out = T()
+    for i in 0..<T.dimension {
+        for j in 0..<T.dimension {
+            // Each cell is Sigma(k=0, M)(lhs[ik] * rhs[kj]
+            for k in 0..<T.dimension {
+                out[i,j] += lhs[i,k] * rhs[k,j]
+            }
+        }
+    }
     return out
 }