fix wrong check to allow condition on streamflow predictions

include/evalhyd/detail/masks.hpp

@@ -21,7 +21,6 @@
 
 #include "maths.hpp"
 
-namespace eh = evalhyd;
 
 typedef std::map<std::string, std::vector<std::vector<std::string>>> msk_tree;
 
@@ -205,7 +204,7 @@ namespace evalhyd
                         }
                         else if (var == "q_prd_median")
                         {
-                            if (q_prd.size() < 1)
+                            if (q_prd.shape(0) == 1)
                             {
                                 throw std::runtime_error(
                                         "condition on streamflow predictions "
@@ -219,7 +218,7 @@ namespace evalhyd
                         else
                         {
                             // i.e. (var == "q_prd_mean")
-                            if (q_prd.size() < 1)
+                            if (q_prd.shape(0) == 1)
                             {
                                 throw std::runtime_error(
                                         "condition on streamflow predictions "
@@ -251,7 +250,7 @@ namespace evalhyd
                         }
                         else  // (str == "quantile")
                         {
-                            return eh::maths::quantile(q, std::stod(num));
+                            return evalhyd::maths::quantile(q, std::stod(num));
                         }
 
                     };