Rename PPV and NPV variables and add aliases

Author: GBrelurut

mapie/risk_control/risks.py

@@ -155,18 +155,24 @@ def get_value_and_effective_sample_size(
     higher_is_better=False,
 )
 
-precision_positive = BinaryClassificationRisk(
+positive_predicted_value = BinaryClassificationRisk(
     risk_occurrence=lambda y_true, y_pred: y_pred == y_true,
     risk_condition=lambda y_true, y_pred: y_pred == 1,
     higher_is_better=True,
 )
 
-precision_negative = BinaryClassificationRisk(
+ppv = positive_predicted_value
+precision_positive = ppv
+
+negative_predicted_value = BinaryClassificationRisk(
     risk_occurrence=lambda y_true, y_pred: y_pred == y_true,
     risk_condition=lambda y_true, y_pred: y_pred == 0,
     higher_is_better=True,
 )
 
+npv = negative_predicted_value
+precision_negative = npv
+
 abstention_rate = BinaryClassificationRisk(
     risk_occurrence=lambda y_true, y_pred: np.isnan(y_pred),
     risk_condition=lambda y_true, y_pred: np.repeat(True, len(y_true)),