Comparing python objects (such as list/tuple) with mlx.core.array (#920)

* add implicit conversion of list to array for equality constraint

* add tests for array equality

* add test for tuple and array equality

* return False if __eq__ arg is list or tuple

* write tests for equality

* update the rule of comparison for __ge__/__gt__/__lt__/__le__

* add a helper function for detecting mlx.core.array

* return true in case fo inequality

* debug minor issue regarding detecting mlx array

* add tests for inequality comparisons

* add name for contribution

* reformat files using pre-commit

* update tests for float

* update tests for inequality

* raise exception in case of invalid comparisons

* use isinstance instead of string comparison

* replace "is_convirtable_to_array" with previous logic

* remove throwing exceptions for other operations

* just a comment

* minor changes for efficiency

* optimize a utils function

* change the function name

* Update ACKNOWLEDGMENTS.md

---------

Co-authored-by: Awni Hannun <awni.hannun@gmail.com>

python/tests/test_array.py

@@ -89,6 +89,121 @@ class TestDtypes(mlx_tests.MLXTestCase):
                 self.assertListEqual(list(z.shape), list(y.shape))
 
 
+class TestEquality(mlx_tests.MLXTestCase):
+    def test_array_eq_array(self):
+        a = mx.array([1, 2, 3])
+        b = mx.array([1, 2, 3])
+        c = mx.array([1, 2, 4])
+        self.assertTrue(mx.all(a == b))
+        self.assertFalse(mx.all(a == c))
+
+    def test_array_eq_scalar(self):
+        a = mx.array([1, 2, 3])
+        b = 1
+        c = 4
+        d = 2.5
+        e = mx.array([1, 2.5, 3.25])
+        self.assertTrue(mx.any(a == b))
+        self.assertFalse(mx.all(a == c))
+        self.assertFalse(mx.all(a == d))
+        self.assertTrue(mx.any(a == e))
+
+    def test_list_equals_array(self):
+        a = mx.array([1, 2, 3])
+        b = [1, 2, 3]
+        c = [1, 2, 4]
+
+        # mlx array equality returns false if is compared with any kind of
+        # object which is not an mlx array
+        self.assertFalse(a == b)
+        self.assertFalse(a == c)
+
+    def test_tuple_equals_array(self):
+        a = mx.array([1, 2, 3])
+        b = (1, 2, 3)
+        c = (1, 2, 4)
+
+        # mlx array equality returns false if is compared with any kind of
+        # object which is not an mlx array
+        self.assertFalse(a == b)
+        self.assertFalse(a == c)
+
+
+class TestInequality(mlx_tests.MLXTestCase):
+    def test_array_ne_array(self):
+        a = mx.array([1, 2, 3])
+        b = mx.array([1, 2, 3])
+        c = mx.array([1, 2, 4])
+        self.assertFalse(mx.any(a != b))
+        self.assertTrue(mx.any(a != c))
+
+    def test_array_ne_scalar(self):
+        a = mx.array([1, 2, 3])
+        b = 1
+        c = 4
+        d = 1.5
+        e = 2.5
+        f = mx.array([1, 2.5, 3.25])
+        self.assertFalse(mx.all(a != b))
+        self.assertTrue(mx.any(a != c))
+        self.assertTrue(mx.any(a != d))
+        self.assertTrue(mx.any(a != e))
+        self.assertFalse(mx.all(a != f))
+
+    def test_list_not_equals_array(self):
+        a = mx.array([1, 2, 3])
+        b = [1, 2, 3]
+        c = [1, 2, 4]
+
+        # mlx array inequality returns true if is compared with any kind of
+        # object which is not an mlx array
+        self.assertTrue(a != b)
+        self.assertTrue(a != c)
+
+    def test_tuple_not_equals_array(self):
+        a = mx.array([1, 2, 3])
+        b = (1, 2, 3)
+        c = (1, 2, 4)
+
+        # mlx array inequality returns true if is compared with any kind of
+        # object which is not an mlx array
+        self.assertTrue(a != b)
+        self.assertTrue(a != c)
+
+    def test_obj_inequality_array(self):
+        str_ = "hello"
+        a = mx.array([1, 2, 3])
+        lst_ = [1, 2, 3]
+        tpl_ = (1, 2, 3)
+
+        # check if object comparison(</>/<=/>=) with mlx array should throw an exception
+        # if not, the tests will fail
+        with self.assertRaises(ValueError):
+            a < str_
+        with self.assertRaises(ValueError):
+            a > str_
+        with self.assertRaises(ValueError):
+            a <= str_
+        with self.assertRaises(ValueError):
+            a >= str_
+        with self.assertRaises(ValueError):
+            a < lst_
+        with self.assertRaises(ValueError):
+            a > lst_
+        with self.assertRaises(ValueError):
+            a <= lst_
+        with self.assertRaises(ValueError):
+            a >= lst_
+        with self.assertRaises(ValueError):
+            a < tpl_
+        with self.assertRaises(ValueError):
+            a > tpl_
+        with self.assertRaises(ValueError):
+            a <= tpl_
+        with self.assertRaises(ValueError):
+            a >= tpl_
+
+
 class TestArray(mlx_tests.MLXTestCase):
     def test_array_basics(self):
         x = mx.array(1)