Components: Switch from factory methods to prototype objects

miplearn/components/primal.py

@@ -50,18 +50,18 @@ class PrimalSolutionComponent(Component):
 
     def __init__(
         self,
-        classifier: Callable[[], Classifier] = lambda: AdaptiveClassifier(),
+        classifier: Classifier = AdaptiveClassifier(),
         mode: str = "exact",
-        threshold: Callable[[], Threshold] = lambda: MinPrecisionThreshold(
-            [0.98, 0.98]
-        ),
+        threshold: Threshold = MinPrecisionThreshold([0.98, 0.98]),
     ) -> None:
+        assert isinstance(classifier, Classifier)
+        assert isinstance(threshold, Threshold)
         assert mode in ["exact", "heuristic"]
         self.mode = mode
         self.classifiers: Dict[Hashable, Classifier] = {}
         self.thresholds: Dict[Hashable, Threshold] = {}
-        self.threshold_factory = threshold
-        self.classifier_factory = classifier
+        self.threshold_prototype = threshold
+        self.classifier_prototype = classifier
         self.stats: Dict[str, float] = {}
         self._n_free = 0
         self._n_zero = 0
@@ -114,8 +114,8 @@ class PrimalSolutionComponent(Component):
         y: Dict[str, np.ndarray],
     ) -> None:
         for category in x.keys():
-            clf = self.classifier_factory()
-            thr = self.threshold_factory()
+            clf = self.classifier_prototype.clone()
+            thr = self.threshold_prototype.clone()
             clf.fit(x[category], y[category])
             thr.fit(clf, x[category], y[category])
             self.classifiers[category] = clf