diff -Nur RGBDemo-0.4.0-Source.orig/nestk/ntk/numeric/levenberg_marquart_minimizer.cpp RGBDemo-0.4.0-Source/nestk/ntk/numeric/levenberg_marquart_minimizer.cpp
--- RGBDemo-0.4.0-Source.orig/nestk/ntk/numeric/levenberg_marquart_minimizer.cpp	2011-02-05 01:49:08.000000000 +0100
+++ RGBDemo-0.4.0-Source/nestk/ntk/numeric/levenberg_marquart_minimizer.cpp	2011-12-27 03:03:37.000000000 +0100
@@ -63,7 +63,7 @@
   }
 
 private:
-  mutable CostFunction& m_cost_function;
+  CostFunction& m_cost_function;
   mutable std::vector<double> m_current_input;
   mutable std::vector<double> m_current_output;
   int m_input_dimension;