From ea4a0feb3a1a6f7513839ecfd0b492b48795515a Mon Sep 17 00:00:00 2001
From: Tadas Baltrusaitis <tadyla@gmail.com>
Date: Sat, 30 Sep 2017 11:33:15 +0100
Subject: [PATCH] Changing division to multiplication, a decent speedup.

---
 lib/local/LandmarkDetector/src/CEN_patch_expert.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/local/LandmarkDetector/src/CEN_patch_expert.cpp b/lib/local/LandmarkDetector/src/CEN_patch_expert.cpp
index 22c317b6..115dded9 100644
--- a/lib/local/LandmarkDetector/src/CEN_patch_expert.cpp
+++ b/lib/local/LandmarkDetector/src/CEN_patch_expert.cpp
@@ -367,9 +367,12 @@ void im2colBiasSparseContrastNorm(const cv::Mat_<float>& input, int width, int h
 				norm = 1;
 			}
 
+			// Flip multiplication to division for speed
+			norm = 1.0 / norm;
+
 			for (size_t x = 1; x < width*height + 1; ++x)
 			{
-				Mo[x] /= norm;
+				Mo[x] *= norm;
 			}
 
 			rowIdx++;