-static double dichotomy(double init, double diff(double, void*), void* var_cnst, double min_error);
-// computes the value of the differential of constraint param_cnst applied to lambda
-static double partial_diff_lambda(double lambda, void* param_cnst);
+static double dichotomy(double init, double diff(double, const s_lmm_constraint_t&), const s_lmm_constraint_t& cnst,
+ double min_error);
+// computes the value of the differential of constraint cnst applied to lambda
+static double partial_diff_lambda(double lambda, const s_lmm_constraint_t& cnst);