diff --git a/sklearn2pmml/ensemble/__init__.py b/sklearn2pmml/ensemble/__init__.py
index 9472d09..6c073ea 100644
--- a/sklearn2pmml/ensemble/__init__.py
+++ b/sklearn2pmml/ensemble/__init__.py
@@ -342,7 +342,7 @@ def _eval_step_mask(self, X, predicate):
 
 	def fit(self, X, y, **fit_params):
 		X_eval = self._to_evaluation_dataset(X)
-		mask = numpy.zeros(X.shape[0], dtype = bool)
+		mask = numpy.full(X.shape[0], fill_value = False)
 		for name, estimator, predicate in self.steps:
 			step_mask = self._eval_step_mask(X_eval, predicate)
 			step_mask[mask] = False
@@ -358,7 +358,7 @@ def fit(self, X, y, **fit_params):
 	def _predict(self, X, predict_method):
 		result = None
 		X_eval = self._to_evaluation_dataset(X)
-		mask = numpy.zeros(X.shape[0], dtype = bool)
+		mask = numpy.full(X.shape[0], fill_value = False)
 		for name, estimator, predicate in self.steps:
 			step_mask = self._eval_step_mask(X_eval, predicate)
 			step_mask[mask] = False
diff --git a/sklearn2pmml/preprocessing/__init__.py b/sklearn2pmml/preprocessing/__init__.py
index b7369cc..d2094e2 100644
--- a/sklearn2pmml/preprocessing/__init__.py
+++ b/sklearn2pmml/preprocessing/__init__.py
@@ -657,7 +657,7 @@ def _eval_step_mask(self, X, predicate):
 
 	def fit(self, X, y = None):
 		X_eval = self._to_evaluation_dataset(X)
-		mask = numpy.zeros(X.shape[0], dtype = bool)
+		mask = numpy.full(X.shape[0], fill_value = False)
 		for name, transformer, predicate in self.steps:
 			step_mask = numpy.logical_not(mask)
 			step_mask_eval = self._eval_step_mask(X_eval[step_mask], predicate)
@@ -673,7 +673,7 @@ def fit(self, X, y = None):
 	def transform(self, X):
 		result = None
 		X_eval = self._to_evaluation_dataset(X)
-		mask = numpy.zeros(X.shape[0], dtype = bool)
+		mask = numpy.full(X.shape[0], fill_value = False)
 		for name, transformer, predicate in self.steps:
 			step_mask = numpy.logical_not(mask)
 			step_mask_eval = self._eval_step_mask(X_eval[step_mask], predicate)