From 57ee6d7dfb9dd609345a670ea052a485cf46b284 Mon Sep 17 00:00:00 2001
From: Marcel Kronfeld <makron@gmx.net>
Date: Thu, 5 Aug 2010 09:36:45 +0000
Subject: [PATCH] Bugfix of F2 derivative

---
 src/eva2/server/go/problems/F2Problem.java | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/eva2/server/go/problems/F2Problem.java b/src/eva2/server/go/problems/F2Problem.java
index 0bac1b06..a5fc9d61 100644
--- a/src/eva2/server/go/problems/F2Problem.java
+++ b/src/eva2/server/go/problems/F2Problem.java
@@ -60,9 +60,9 @@ public class F2Problem extends AbstractProblemDoubleOffset implements InterfaceL
         for (int i = 0; i < dim-1; i++) {
         	xi=x[i]-m_XOffSet;
         	xii=x[i+1]-m_XOffSet;
-        	
-            result[i] += (-200.*xii+200.*xi+2.*xi-2);
-            result[i+1] += (200.*xii-200*xi);
+
+        	result[i] += 400*xi*(xi*xi-xii) + 2*xi-2;
+        	result[i+1] += -200 * (xi*xi - xii);
         }
         return result;
 	}