add serde support for XGBoostRegressor

Author: cmmartin

src/xgboost/xgb_regressor.rs

@@ -122,6 +122,7 @@ impl Objective {
 /// This is a recursive data structure where each `TreeRegressor` is a node
 /// that can have a left and a right child, also of type `TreeRegressor`.
 #[allow(dead_code)]
+#[derive(Debug)]
 struct TreeRegressor<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>> {
     left: Option<Box<TreeRegressor<TX, TY, X, Y>>>,
     right: Option<Box<TreeRegressor<TX, TY, X, Y>>>,
@@ -374,6 +375,7 @@ impl<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>>
 /// Parameters for the `jRegressor` model.
 ///
 /// This struct holds all the hyperparameters that control the training process.
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Clone, Debug)]
 pub struct XGRegressorParameters {
     /// The number of boosting rounds or trees to build.
@@ -494,6 +496,8 @@ impl XGRegressorParameters {
 }
 
 /// An Extreme Gradient Boosting (XGBoost) model for regression and classification tasks.
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[derive(Debug)]
 pub struct XGRegressor<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>> {
     regressors: Option<Vec<TreeRegressor<TX, TY, X, Y>>>,
     parameters: Option<XGRegressorParameters>,