From a23d726bab3c292733247b9818b6b62cd2249081 Mon Sep 17 00:00:00 2001
From: ernestotapiar <ernestotapiar@users.noreply.github.com>
Date: Fri, 14 Apr 2017 15:41:25 +0200
Subject: [PATCH] Corrected typo that generated an erroneus Hessian of Brown's
 function. (#534)

---
 dlib/test/optimization_test_functions.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlib/test/optimization_test_functions.cpp b/dlib/test/optimization_test_functions.cpp
index 5a936169a..1cded50ee 100644
--- a/dlib/test/optimization_test_functions.cpp
+++ b/dlib/test/optimization_test_functions.cpp
@@ -378,7 +378,7 @@ namespace dlib
                 h(0,3) = h(0,3) + 8.0E+00 * f1 * f2 * df1dx1 * df2dx4;
 
                 h(1,0) = h(1,0) + 12.0E+00 * pow(f1,2) * df1dx2 * df1dx1 + 4.0E+00 * pow(f2,2) * df1dx2 * df1dx1;
-                h(1,1) = h(1,1) + 12.0E+00 * pow(f1,2) * df1dx2 * df1dx2 + 4.0E+00 * pow(f2,2) * df1dx2 * df1dx1;
+                h(1,1) = h(1,1) + 12.0E+00 * pow(f1,2) * df1dx2 * df1dx2 + 4.0E+00 * pow(f2,2) * df1dx2 * df1dx2;
                 h(1,2) = h(1,2) + 8.0E+00 * f1 * f2 * df1dx2 * df2dx3;
                 h(1,3) = h(1,3) + 8.0E+00 * f1 * f2 * df1dx2 * df2dx4;