src/radmeth/radmeth_model.hpp: added accessor for number of parameters

Author: andrewdavidsmith

src/radmeth/radmeth_model.hpp

@@ -107,6 +107,11 @@ struct Regression {
     return design.n_groups();
   }
 
+  [[nodiscard]] std::size_t
+  n_params() const {
+    return n_factors() + 1;
+  }
+
   [[nodiscard]] std::size_t
   props_size() const {
     return std::size(props.mc);