Use references

dune/tectonic/localnonlinearity.hh

@@ -21,7 +21,7 @@ template <int dimension> class LocalNonlinearity {
 
   LocalNonlinearity(shared_ptr<NiceFunction const> func) : func_(func) {}
 
-  double operator()(VectorType const x) const {
+  double operator()(VectorType const &x) const {
     double ret;
     func_->evaluate(x.two_norm(), ret);
     return ret;
@@ -29,7 +29,7 @@ template <int dimension> class LocalNonlinearity {
 
   // directional subdifferential: at u on the line u + t*v
   // u and v are assumed to be non-zero
-  void directionalSubDiff(VectorType const u, VectorType const v,
+  void directionalSubDiff(VectorType const &u, VectorType const &v,
                           Interval<double> &D) const {
     if (u.two_norm() == 0) {
       D[0] = D[1] = func_->rightDifferential(0) * v.two_norm();
@@ -47,12 +47,12 @@ template <int dimension> class LocalNonlinearity {
     }
   }
 
-  void upperGradient(VectorType const x, VectorType &ret) const {
+  void upperGradient(VectorType const &x, VectorType &ret) const {
     ret = x;
     ret *= func_->rightDifferential(x.two_norm()) / x.two_norm();
   }
 
-  void lowerGradient(VectorType const x, VectorType &ret) const {
+  void lowerGradient(VectorType const &x, VectorType &ret) const {
     ret = x;
     ret *= func_->leftDifferential(x.two_norm()) / x.two_norm();
   }