From 4306a94379847613505517337634495bb8cf4037 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Mon, 6 Mar 2017 21:36:04 +1100
Subject: [PATCH] matrix: add assignment-multiplication operator

---
 matrix.hpp | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/matrix.hpp b/matrix.hpp
index 05463b5b..e66cf5a7 100644
--- a/matrix.hpp
+++ b/matrix.hpp
@@ -143,7 +143,22 @@ namespace util {
         size_t R1, size_t C1,
         size_t R2, size_t C2,
         typename T
-    > constexpr matrix<R1,C2,T> operator* (const matrix<R1,C1,T>&, const matrix<R2,C2,T>&);
+    >
+    constexpr
+    matrix<R1,C2,T>
+    operator* (const matrix<R1,C1,T>&, const matrix<R2,C2,T>&);
+
+
+    //-------------------------------------------------------------------------
+    template <
+        size_t R1, size_t C1,
+        size_t R2, size_t C2,
+        typename T
+    >
+    constexpr
+    matrix<R1,C2,T>&
+    operator*= (matrix<R1,C1,T> &a, const matrix<R2,C2,T> &b)
+    { return a = a * b; };
 
 
     ///////////////////////////////////////////////////////////////////////////