diff --git a/dune/tectonic/localfriction.hh b/dune/tectonic/localfriction.hh
index 5c67dc38e1b496ce2f0306c3f8fb1e73521b0cbd..a202e7f224b46bb27a76e630eb18488779684bf9 100644
--- a/dune/tectonic/localfriction.hh
+++ b/dune/tectonic/localfriction.hh
@@ -12,23 +12,6 @@
 
 #include "frictionpotential.hh"
 
-// In order to compute (x * y) / |x|, compute x/|x| first
-template <class Vector>
-double dotFirstNormalised(Vector const &x, Vector const &y) {
-  double const xnorm = x.two_norm();
-  if (xnorm <= 0.0)
-    return 0.0;
-
-  size_t const xsize = x.size();
-  assert(xsize == y.size());
-
-  double sum = 0;
-  for (size_t i = 0; i < xsize; ++i)
-    sum += x[i] / xnorm * y[i];
-
-  return sum;
-}
-
 template <size_t dimension> class LocalFriction {
 public:
   using VectorType = Dune::FieldVector<double, dimension>;
@@ -63,7 +46,7 @@ template <size_t dimension> class LocalFriction {
     if (xnorm <= 0.0)
       D[0] = D[1] = func->differential(0.0) * v.two_norm();
     else
-      D[0] = D[1] = func->differential(xnorm) * dotFirstNormalised(x, v);
+      D[0] = D[1] = func->differential(xnorm) * (x * v) / xnorm;
   }
 
   /** Formula for the derivative: