random functor added

extensions/Tools.h

@@ -9,8 +9,29 @@
 #include <boost/fusion/include/boost_array.hpp>
 
 #include "MetaTools.h"
+#include "Helpers.h"
 
 namespace tools {
+  
+  struct Random : AbstractFunction<double,WorldVector<double> >
+  {
+    Random(double mean_, double amplitude_) : mean(mean_), amplitude(amplitude_)
+    {
+      #ifdef HAVE_PARALLEL_DOMAIN_AMDIS
+      mpi::startRand();
+      #else
+      std::srand(Helpers::getRandomSeed());
+      #endif
+    }
+    double operator()(const WorldVector<double> &x) const
+    {
+      return mean + amplitude * (std::rand() / static_cast<double>(RAND_MAX) - 0.5);
+    }
+    
+  private:
+    double mean;
+    double amplitude;
+  };
 
 /// Quadrature Rules
 ///____________________________________________________________________________________