Add method to set truncation tolerance

dune/tnnmg/functionals/bcqfconstrainedlinearization.hh

@@ -96,6 +96,11 @@ public:
     truncationTolerance_(1e-10)
   {}
 
+  void setTruncationTolerance(double tolerance)
+  {
+    truncationTolerance_ = tolerance;
+  }
+
   void bind(const Vector& x)
   {
     negativeGradient_ = derivative(f_)(x);