remove declarations of unused and undefined functions

src/probabilist/evaluator.h

@@ -129,15 +129,6 @@ namespace evalhyd
             void calc_QS();
             void calc_CRPS();
         };
-
-        xt::xtensor<double, 3> is_above_threshold(
-                const xt::xtensor<double, 2>&, const xt::xtensor<double, 1>&
-        );
-
-        xt::xtensor<double, 3> is_below_threshold(
-                const xt::xtensor<double, 2>&, const xt::xtensor<double, 1>&
-        );
-
     }
 }