feat: add cross_product (#1252)

* feat: add cross_product

* lint

* python binding

* refactor: Improve error message for cross_product function

* refactor: more close to numpy cross product

* refactor: improve error message for cross_product function

* finish

* fix acks

* allow old numpy

* doc

---------

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

tests/linalg_tests.cpp

@@ -390,3 +390,48 @@ TEST_CASE("test matrix pseudo-inverse") {
     CHECK(allclose(A_pinv_again, A_pinv).item<bool>());
   }
 }
+
+TEST_CASE("test cross product") {
+  using namespace mlx::core::linalg;
+
+  // Test for vectors of length 3
+  array a = array({1.0, 2.0, 3.0});
+  array b = array({4.0, 5.0, 6.0});
+
+  array expected = array(
+      {2.0 * 6.0 - 3.0 * 5.0, 3.0 * 4.0 - 1.0 * 6.0, 1.0 * 5.0 - 2.0 * 4.0});
+
+  array result = cross(a, b);
+  CHECK(allclose(result, expected).item<bool>());
+
+  // Test for vectors of length 3 with negative values
+  a = array({-1.0, -2.0, -3.0});
+  b = array({4.0, -5.0, 6.0});
+
+  expected = array(
+      {-2.0 * 6.0 - (-3.0 * -5.0),
+       -3.0 * 4.0 - (-1.0 * 6.0),
+       -1.0 * -5.0 - (-2.0 * 4.0)});
+
+  result = cross(a, b);
+  CHECK(allclose(result, expected).item<bool>());
+
+  // Test for incorrect vector size (should throw)
+  b = array({1.0, 2.0});
+  expected = array(
+      {-2.0 * 0.0 - (-3.0 * 2.0),
+       -3.0 * 1.0 - (-1.0 * 0.0),
+       -1.0 * 2.0 - (-2.0 * 1.0)});
+
+  result = cross(a, b);
+  CHECK(allclose(result, expected).item<bool>());
+
+  // Test for vectors of length 3 with integer values
+  a = array({1, 2, 3});
+  b = array({4, 5, 6});
+
+  expected = array({2 * 6 - 3 * 5, 3 * 4 - 1 * 6, 1 * 5 - 2 * 4});
+
+  result = cross(a, b);
+  CHECK(allclose(result, expected).item<bool>());
+}