DEP: deprecate `np.round_`

Closes gh-22617

5 files changed, 21 insertions, 4 deletions

diff --git a/doc/release/upcoming_changes/23302.deprecation.rst b/doc/release/upcoming_changes/23302.deprecation.rst
new file mode 100644
index 000000000..9e36d658c
--- /dev/null
+++ b/doc/release/upcoming_changes/23302.deprecation.rst
@@ -0,0 +1 @@
+* ``np.round_`` is deprecated. Use `np.round` instead. 
diff --git a/numpy/core/__init__.py b/numpy/core/__init__.py
index 1079c41df..f70743cbe 100644
--- a/numpy/core/__init__.py
+++ b/numpy/core/__init__.py
@@ -92,7 +92,7 @@ from . import einsumfunc
 from .einsumfunc import *
 del nt
 
-from .fromnumeric import amax as max, amin as min, round_ as round
+from .fromnumeric import amax as max, amin as min
 from .numeric import absolute as abs
 
 # do this after everything else, to minimize the chance of this misleadingly
diff --git a/numpy/core/fromnumeric.py b/numpy/core/fromnumeric.py
index 7d3336f88..96f585066 100644
--- a/numpy/core/fromnumeric.py
+++ b/numpy/core/fromnumeric.py
@@ -21,7 +21,7 @@ __all__ = [
     'argmin', 'argpartition', 'argsort', 'around', 'choose', 'clip',
     'compress', 'cumprod', 'cumproduct', 'cumsum', 'diagonal', 'mean',
     'ndim', 'nonzero', 'partition', 'prod', 'product', 'ptp', 'put',
-    'ravel', 'repeat', 'reshape', 'resize', 'round_',
+    'ravel', 'repeat', 'reshape', 'resize', 'round', 'round_',
     'searchsorted', 'shape', 'size', 'sometrue', 'sort', 'squeeze',
     'std', 'sum', 'swapaxes', 'take', 'trace', 'transpose', 'var',
 ]
@@ -3337,6 +3337,9 @@ def around(a, decimals=0, out=None):
     return _wrapfunc(a, 'round', decimals=decimals, out=out)
 
 
+round = around
+
+
 def _mean_dispatcher(a, axis=None, dtype=None, out=None, keepdims=None, *,
                      where=None):
     return (a, where, out)
@@ -3760,10 +3763,17 @@ def round_(a, decimals=0, out=None):
     `~numpy.round_` is a disrecommended backwards-compatibility
     alias of `~numpy.around` and `~numpy.round`.
 
+    .. deprecated:: 1.25.0
+        ``round_`` is deprecated as of NumPy 1.25.0, and will be
+        removed in NumPy 2.0. Please use `round` instead.
+
     See Also
     --------
     around : equivalent function; see for details.
     """
+    warnings.warn("`round_` is deprecated as of NumPy 1.25.0, and will be "
+                  "removed in NumPy 2.0. Please use `round` instead.",
+                  DeprecationWarning, stacklevel=2)
     return around(a, decimals=decimals, out=out)
 
 
diff --git a/numpy/core/tests/test_deprecations.py b/numpy/core/tests/test_deprecations.py
index ac4761b50..8ff52c885 100644
--- a/numpy/core/tests/test_deprecations.py
+++ b/numpy/core/tests/test_deprecations.py
@@ -901,3 +901,9 @@ class TestDeprecatedFinfo(_DeprecationTestCase):
     # Deprecated in NumPy 1.25, 2023-01-16
     def test_deprecated_none(self):
         self.assert_deprecated(np.finfo, args=(None,))
+
+
+class TestRound_(_DeprecationTestCase):
+    # 2023-02-28, 1.25.0
+    def test_round_(self):
+        self.assert_deprecated(lambda: np.round_(np.array([1.5, 2.5, 3.5])))
diff --git a/numpy/ma/tests/test_extras.py b/numpy/ma/tests/test_extras.py
index 38603fb84..e59ba3656 100644
--- a/numpy/ma/tests/test_extras.py
+++ b/numpy/ma/tests/test_extras.py
@@ -387,8 +387,8 @@ class TestConcatenator:
         # Tests mr_ on 2D arrays.
         a_1 = np.random.rand(5, 5)
         a_2 = np.random.rand(5, 5)
-        m_1 = np.round_(np.random.rand(5, 5), 0)
-        m_2 = np.round_(np.random.rand(5, 5), 0)
+        m_1 = np.round(np.random.rand(5, 5), 0)
+        m_2 = np.round(np.random.rand(5, 5), 0)
         b_1 = masked_array(a_1, mask=m_1)
         b_2 = masked_array(a_2, mask=m_2)
         # append columns