max_drop_(0)
max_drop_(0), max_f_(0)
      drop_convergence_test(        SizeType p = 5,        FloatType max_drop_eps = FloatType(1.e-5),        FloatType iteration_coefficient = FloatType(2))      : p_(p),        max_drop_eps_(max_drop_eps),        iteration_coefficient_(iteration_coefficient),        max_drop_(0)      {        if (p_ < 2) {          throw error_improper_input_parameter("p < 2.");        }        if (max_drop_eps_ < FloatType(0)) {          throw error_improper_input_parameter("max_drop_eps < 0.");        }        if (iteration_coefficient_ < FloatType(1)) {          throw error_improper_input_parameter("iteration_coefficient < 1.");        }      }