removed const

Author: Teseo Schneider

src/polysolve/nonlinear/Problem.hpp

@@ -30,8 +30,8 @@ namespace polysolve::nonlinear
         virtual void gradient(const TVector &x, TVector &gradv) override = 0;
         virtual void hessian(const TVector &x, THessian &hessian) = 0;
 
-        virtual bool is_step_valid(const TVector &x0, const TVector &x1) const { return true; }
-        virtual double max_step_size(const TVector &x0, const TVector &x1) const { return 1; }
+        virtual bool is_step_valid(const TVector &x0, const TVector &x1) { return true; }
+        virtual double max_step_size(const TVector &x0, const TVector &x1) { return 1; }
 
         virtual void line_search_begin(const TVector &x0, const TVector &x1) {}
         virtual void line_search_end() {}