statistics.utils: Fix stats for sparse when last column missing

`np.bincount` has a length of the maximal element and can hence be shorter than the number of columns (e.g. when some of the last columns have all zeros). This forces it to count non zero elements for all columns.
biolab · Jul 15, 2016 · ff2a5b4 · ff2a5b4
1 parent b77c021
commit ff2a5b4
Show file tree

Hide file tree

Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/Orange/statistics/util.py b/Orange/statistics/util.py
@@ -178,7 +178,7 @@ def stats(X, weights=None, compute_variance=False):
         if compute_variance:
             raise NotImplementedError
 
-        non_zero = np.bincount(X.nonzero()[1])
+        non_zero = np.bincount(X.nonzero()[1], minlength=X.shape[1])
         X = X.tocsc()
         return np.column_stack((
             X.min(axis=0).toarray().ravel(),

diff --git a/Orange/tests/test_statistics.py b/Orange/tests/test_statistics.py
@@ -41,3 +41,11 @@ def test_stats_sparse(self):
                                            [0, 1, .2, 0, 4, 1],
                                            [0, 1, .2, 0, 4, 1],
                                            [0, 1, .2, 0, 4, 1]])
+
+        # assure last two columns have just zero elements
+        X = X[:3]
+        np.testing.assert_equal(stats(X), [[0, 1, 1/3, 0, 4, 1],
+                                           [0, 1, 1/3, 0, 4, 1],
+                                           [0, 1, 1/3, 0, 4, 1],
+                                           [0, 0,   0, 0, 5, 0],
+                                           [0, 0,   0, 0, 5, 0]])