#1 Add min_samples_split

Fix #1

stree/Strees.py

@@ -131,6 +131,7 @@ class Stree(BaseEstimator, ClassifierMixin):
         max_depth: int = None,
         tol: float = 1e-4,
         use_predictions: bool = False,
+        min_samples_split: int = 0,
     ):
         self.max_iter = max_iter
         self.C = C
@@ -138,6 +139,7 @@ class Stree(BaseEstimator, ClassifierMixin):
         self.use_predictions = use_predictions
         self.max_depth = max_depth
         self.tol = tol
+        self.min_samples_split = min_samples_split
 
     def _more_tags(self) -> dict:
         """Required by sklearn to tell that this estimator is a binary classifier
@@ -206,7 +208,11 @@ class Stree(BaseEstimator, ClassifierMixin):
         :return: [description]
         :rtype: np.array
         """
-        return data > 0
+        return (
+            data > 0
+            if data.shape[0] >= self.min_samples_split
+            else np.ones((data.shape[0], 1), dtype=bool)
+        )
 
     def fit(
         self, X: np.ndarray, y: np.ndarray, sample_weight: np.array = None

stree/Strees_grapher.py

@@ -133,7 +133,6 @@ class Stree_grapher(Stree):
             os.environ.pop("TESTING")
         except KeyError:
             pass
-        plt.close("all")
 
     def _copy_tree(self, node: Snode) -> Snode_graph:
         mirror = Snode_graph(node)

stree/tests/Strees_test.py

@@ -315,6 +315,17 @@ class Stree_test(unittest.TestCase):
         tcl = Stree()
         self.assertEqual(0, len(list(tcl)))
 
+    def test_min_samples_split(self):
+        tcl_split = Stree(min_samples_split=3)
+        tcl_nosplit = Stree(min_samples_split=4)
+        dataset = [[1], [2], [3]], [1, 1, 0]
+        tcl_split.fit(*dataset)
+        self.assertIsNotNone(tcl_split.tree_.get_down())
+        self.assertIsNotNone(tcl_split.tree_.get_up())
+        tcl_nosplit.fit(*dataset)
+        self.assertIsNone(tcl_nosplit.tree_.get_down())
+        self.assertIsNone(tcl_nosplit.tree_.get_up())
+
 
 class Snode_test(unittest.TestCase):
     def __init__(self, *args, **kwargs):