use with stiff

NonLinearSolver/modelReduction/ANNUtils.cpp

@@ -236,7 +236,7 @@ void ArtificialNN::predict(const fullMatrix<double>& yIn, fullMatrix<double>& yO
   }
   yOut = yIn;
   static std::vector<fullMatrix<double> > all_Dy;
-  if (all_Dy.size() != _numLayers)
+  if (all_Dy.size() != _numLayers && stiff)
   {
     all_Dy.resize(_numLayers);
   }