Fix dpnp.mgrid/dpnp.ogrid inconsistency for complex steps with non-integer magnitude

CHANGELOG.md

@@ -50,6 +50,7 @@ This release is compatible with NumPy 2.5.
 * Fixed `PytestRemovedIn10Warning` raised by `pytest` 9.1.0 by converting class-scoped fixtures to class methods [#2952](https://github.com/IntelPython/dpnp/pull/2952)
 * Fixed `dpnp.linalg.svd(..., hermitian=True)` returning a non-unitary `vh` for singular input arrays due to a zero sign appearing [#2954](https://github.com/IntelPython/dpnp/pull/2954)
 * Fixed scalar conversion of size-one `dpnp.tensor.usm_ndarray` (e.g. `int()`, `float()`, indexing) which failed with NumPy 2.5 after the in-place `ndarray.shape` assignment was deprecated [#2958](https://github.com/IntelPython/dpnp/pull/2958)
+* Fixed `dpnp.mgrid` and `dpnp.ogrid` to return consistent results between single-slice and tuple-of-slices syntax when the step is a complex number with a non-integer magnitude (e.g. `2.5j`) [#2971](https://github.com/IntelPython/dpnp/pull/2971)
 
 ### Security
 

dpnp/dpnp_algo/dpnp_arraycreation.py

@@ -356,11 +356,10 @@ def __getitem__(self, key):
             if start is None:
                 start = 0
             if isinstance(step, complex):
-                step = abs(step)
-                length = int(step)
+                step_float = abs(step)
+                step = length = int(step_float)
                 if step != 1:
                     step = (stop - start) / float(step - 1)
-                stop = stop + step
                 return (
                     dpnp.arange(
                         0,

dpnp/tests/test_arraycreation.py

@@ -1071,6 +1071,8 @@ def check_results(self, result, expected):
             slice(0, 5, 0.5),  # float step
             slice(0, 5, 1j),  # complex step
             slice(0, 5, 5j),  # complex step
+            slice(0, 10, 2.5j),  # complex step with non-integer magnitude
+            slice(0, 10, 3.5j),  # non-integer magnitude with interior points
             slice(None, 5, 1),  # no start
             slice(0, 5, None),  # no step
         ],
@@ -1090,6 +1092,10 @@ def test_single_slice(self, grid, slice):
                 slice(0.0, 5, 1),
                 slice(0, 10, 1j),
             ),  # float start and complex step
+            (
+                slice(0, 10, 2.5j),
+                slice(0, 10, 3.5j),
+            ),  # complex step with non-integer magnitude
         ],
     )
     def test_md_slice(self, grid, slices):