minor fixes (#631)

* minor fixes

* var with ddof >= nelements

python/tests/test_blas.py

@@ -582,6 +582,25 @@ class TestBlas(mlx_tests.MLXTestCase):
                 self.assertEqual(r.shape, t.shape)
                 self.assertTrue(mx.allclose(r, t, atol=1e-4).item())
 
+    def test_empty_matmul(self):
+        a = mx.array([[], []]).T
+        b = mx.array([[1.0, 2.0], [2.0, 3.0]])
+        c = a @ b
+        mx.eval(c)
+        self.assertEqual(c.shape, (0, 2))
+
+        a = mx.array([[1.0, 2.0], [2.0, 3.0]])
+        b = mx.array([[], []])
+        c = a @ b
+        mx.eval(c)
+        self.assertEqual(c.shape, (2, 0))
+
+        a = mx.array([[], []]).T
+        b = mx.array([[], []])
+        c = a @ b
+        mx.eval(c)
+        self.assertEqual(c.shape, (0, 0))
+
 
 if __name__ == "__main__":
     unittest.main()

python/tests/test_ops.py

@@ -1,4 +1,4 @@
-# Copyright © 2023 Apple Inc.
+# Copyright © 2023-2024 Apple Inc.
 
 import math
 import unittest
@@ -690,6 +690,14 @@ class TestOps(mlx_tests.MLXTestCase):
         self.assertEqual(mx.var(x, axis=0).tolist(), [1.0, 1.0])
         self.assertEqual(mx.var(x, axis=1).tolist(), [0.25, 0.25])
 
+        x = mx.array([1.0, 2.0])
+        out = mx.var(x, ddof=2)
+        self.assertEqual(out.item(), float("inf"))
+
+        x = mx.array([1.0, 2.0])
+        out = mx.var(x, ddof=3)
+        self.assertEqual(out.item(), float("inf"))
+
     def test_abs(self):
         a = mx.array([-1.0, 1.0, -2.0, 3.0])
         result = mx.abs(a)