+template<class T>
+void
+scale_drul (Drul_array<T> *dr, T x)
+{
+ dr->at (LEFT) *= x;
+ dr->at (RIGHT) *= x;
+}
+
+inline Real
+linear_combination (Drul_array<Real> const &d, Real x)
+{
+ return ((1.0 - x) * Real (d.at (LEFT))
+ + (x + 1.0) * Real (d.at (RIGHT))) * 0.5;
+}
+
+#endif /* DRUL_ARRAY_HH */