rename: tangentialDirection -> tangent

dune/tectonic/curvedfunction.hh

@@ -22,15 +22,15 @@ template <class NonlinearityType> class CurvedFunction {
   void subDiff(double m, Interval<double> &D) const {
     VectorType x;
     cartesian(m, x);
-    VectorType tangent;
-    tangentialDirection(m, tangent);
+    VectorType t;
+    tangent(m, t);
 
-    phi.directionalSubDiff(x, tangent, D);
+    phi.directionalSubDiff(x, t, D);
 
     VectorType tmp;
-    A.mv(x, tmp);                      //  Ax
-    tmp -= b;                          //  Ax - b
-    double const dotp = tmp * tangent; // <Ax - b,t>
+    A.mv(x, tmp);                //  Ax
+    tmp -= b;                    //  Ax - b
+    double const dotp = tmp * t; // <Ax - b,t>
     D[0] += dotp;
     D[1] += dotp;
   }
@@ -61,7 +61,7 @@ template <class NonlinearityType> class CurvedFunction {
      Since we x and d are not normalised and the return of
      cartesian() is fixed, we scale the tangent.
   */
-  void tangentialDirection(double m, VectorType &y) const {
+  void tangent(double m, VectorType &y) const {
     y = 0;
     y.axpy(-std::sin(m) * dir.two_norm2(), x);
     y.axpy(std::cos(m) * x.two_norm2(), dir);