More references

src/samplefunctional.hh

@@ -26,7 +26,7 @@ template <int dim> class SampleFunctional {
                    MyNonlinearity<dim> const &phi)
       : A(A), b(b), phi(phi) {}
 
-  double operator()(SmallVector const v) const {
+  double operator()(SmallVector const &v) const {
     SmallVector y;
     A.mv(v, y);            // y = Av
     y /= 2;                // y = 1/2 Av