From c1e0abe08e518f68c41cbd4bbb8631f3d7affea1 Mon Sep 17 00:00:00 2001
From: Jonathan <jonathan.clarke@fivesigma.co.uk>
Date: Wed, 20 Mar 2024 11:06:54 +0000
Subject: [PATCH 1/2] - initial attempt

---
 pandas/_libs/tslibs/offsets.pyx        | 16 +++++++++++
 pandas/tests/tseries/offsets/common.py | 40 ++++++++++++++++++++++++++
 test_fast.sh                           |  2 +-
 3 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/offsets.pyx b/pandas/_libs/tslibs/offsets.pyx
index d799770a57be2..0c6cfd89cc165 100644
--- a/pandas/_libs/tslibs/offsets.pyx
+++ b/pandas/_libs/tslibs/offsets.pyx
@@ -689,6 +689,22 @@ cdef class BaseOffset:
             "does not have a vectorized implementation"
         )
 
+    def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
+        import traceback, sys
+        traceback.print_stack(file=sys.stdout)
+        print(ufunc, method, type(inputs[0]), type(inputs[1]))
+        a, b = inputs
+        if isinstance(a, ndarray) and isinstance(b, BaseOffset):
+            array = a
+            offset = b
+        elif isinstance(b, ndarray) and isinstance(a, BaseOffset):
+            array = b
+            offset = a
+        else:
+            return NotImplemented
+
+        return offset._apply_array(a).astype('M8[ns]')
+
     def rollback(self, dt) -> datetime:
         """
         Roll provided date backward to next offset only if not on offset.
diff --git a/pandas/tests/tseries/offsets/common.py b/pandas/tests/tseries/offsets/common.py
index c12130544e6b2..afcc5ded5cac2 100644
--- a/pandas/tests/tseries/offsets/common.py
+++ b/pandas/tests/tseries/offsets/common.py
@@ -24,6 +24,8 @@
     WeekOfMonth,
 )
 from pandas.compat import IS64
+from pandas import Series, Timedelta, Timestamp
+from numpy.testing import assert_allclose
 
 
 def assert_offset_equal(offset, base, expected):
@@ -205,3 +207,41 @@ def test_compare_str(self):
         assert off != "foo"
         # Note: inequalities are only implemented for Tick subclasses;
         #  tests for this are in test_ticks
+
+    test_dates_sr = Series([Timestamp(2021, 1, 1) + Timedelta(days=d) for d in range(1000)])
+
+    def test_np_array_add(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        a, b = self.offset2, self.test_dates_sr.to_numpy()
+        #breakpoint()
+        c = a + b
+        assert_allclose((self.offset2 + self.test_dates_sr).to_numpy(),
+                        c)
+
+    def test_np_array_radd(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        a, b = self.test_dates_sr.to_numpy(), self.offset2
+        #breakpoint()
+        c = a + b
+        assert_allclose((self.test_dates_sr + self.offset2).to_numpy(),
+                        c)
+
+    def test_np_array_sub(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        assert (self.offset2 - self.test_dates_sr).to_numpy() == self.offset2 - self.test_dates_sr.to_numpy()
+
+    def test_np_array_rsub(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        assert (self.test_dates_sr - self.offset2).to_numpy() == self.test_dates_sr.to_numpy() - self.offset2
\ No newline at end of file
diff --git a/test_fast.sh b/test_fast.sh
index 0120c712e3df8..141c56dc53355 100755
--- a/test_fast.sh
+++ b/test_fast.sh
@@ -5,4 +5,4 @@
 # https://github.com/pytest-dev/pytest/issues/1075
 export PYTHONHASHSEED=$(python -c 'import random; print(random.randint(1, 4294967295))')
 
-pytest pandas --skip-slow --skip-network --skip-db -m "not single_cpu" -n 4 -r sxX "$@"
+pytest pandas/tests/tseries/offsets --skip-slow --skip-network --skip-db -m "not single_cpu" -n 4 -r sxX "$@"

From 7582696f59963471d7d00d471ce055b0d2735fcf Mon Sep 17 00:00:00 2001
From: hottwaj <jonathan.a.clarke@gmail.com>
Date: Wed, 27 Mar 2024 13:06:31 +0000
Subject: [PATCH 2/2] Update pandas/_libs/tslibs/offsets.pyx

Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
---
 pandas/_libs/tslibs/offsets.pyx | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pandas/_libs/tslibs/offsets.pyx b/pandas/_libs/tslibs/offsets.pyx
index 71ec8e24a0356..52d935a70ee45 100644
--- a/pandas/_libs/tslibs/offsets.pyx
+++ b/pandas/_libs/tslibs/offsets.pyx
@@ -457,10 +457,9 @@ cdef class BaseOffset:
 
     def __add__(self, other):
         if util.is_array(other):
-            from pandas.api.types import is_datetime64_any_dtype
             if other.dtype == object:
                 return np.array([self + x for x in other])
-            elif is_datetime64_any_dtype(other):
+            elif other.dtype.kind == "M":
                 return self._apply_array(other).astype(other.dtype)
 
         try: