Add hanning window function (#3124)

python/src/ops.cpp

@@ -1428,6 +1428,28 @@ void init_ops(nb::module_& m) {
       "stream"_a = nb::none(),
       nb::sig(
           "def arange(stop : Union[int, float], step : Union[None, int, float] = None, dtype: Optional[Dtype] = None, *, stream: Union[None, Stream, Device] = None) -> array"));
+  m.def(
+      "hanning",
+      &mlx::core::hanning,
+      "M"_a,
+      nb::kw_only(),
+      "stream"_a = nb::none(),
+      R"pbdoc(
+        Return the Hanning window.
+        
+        The Hanning window is a taper formed by using a weighted cosine.
+
+        .. math::
+          w(n) = 0.5 - 0.5 \cos\left(\frac{2\pi n}{M-1}\right)
+           \qquad 0 \le n \le M-1
+        
+        Args:
+            M (int): Number of points in the output window.
+            
+        Returns:
+            array: The window, with the maximum value normalized to one (the value one
+                   appears only if the number of samples is odd).
+    )pbdoc");
   m.def(
       "linspace",
       [](Scalar start,

python/tests/test_ops.py

@@ -1450,6 +1450,18 @@ class TestOps(mlx_tests.MLXTestCase):
         expected = [0]
         self.assertListEqual(a.tolist(), expected)
 
+    def test_hanning_general(self):
+        a = mx.hanning(10)
+        expected = np.hanning(10)
+        self.assertTrue(np.allclose(a, expected, atol=1e-5))
+
+        a = mx.hanning(1)
+        self.assertEqual(a.item(), 1.0)
+
+        a = mx.hanning(0)
+        self.assertEqual(a.size, 0)
+        self.assertEqual(a.dtype, mx.float32)
+
     def test_unary_ops(self):
         def test_ops(npop, mlxop, x, y, atol, rtol):
             r_np = npop(x)