Vendor numpy `median`, `percentile`, and `quantile` reduction tests #567

brandon-b-miller · 2025-10-31T18:15:26Z

Follow up #523

Co-authored-by: Phillip Cloud <417981+cpcloud@users.noreply.github.com>

…uctions-2

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brandon-b-miller · 2026-01-21T17:03:31Z

/ok to test

greptile-apps · 2026-01-21T17:07:26Z

Greptile Summary

Vendors comprehensive tests for np.median, np.percentile, np.quantile, np.nanpercentile, and np.nanquantile from upstream NumPy test suite. Adds necessary infrastructure including make_constant_list method and ufunc implementations for np.isfinite and np.multiply.

Key changes:

Added NRTEnablingCUDATestCase base class to centralize NRT config management across test files
Implemented make_constant_list to create constant lists in CUDA constant address space
Added 260+ lines of vendored reduction tests covering edge cases, empty arrays, finite/infinite values
Refactored test_array_methods.py to use new base class
Removed memcpy fast path optimization in _array_copy function (performance regression)
Added new test file test_array_methods.py with array copy verification

Issues found:

Performance regression in arrayobj.py:5506-5531 where memcpy fast path was removed
Redundant NRT config management in test_array_reductions.py:25-36 conflicts with parent class

Confidence Score: 3/5

This PR adds valuable test coverage but introduces a performance regression and config management issues
Score reflects significant performance regression from removed memcpy optimization and potential config conflicts from redundant NRT state management. Test additions are comprehensive but the infrastructure changes need fixes.
Pay close attention to numba_cuda/numba/cuda/np/arrayobj.py (memcpy fast path removed) and numba_cuda/numba/cuda/tests/cudapy/test_array_reductions.py (redundant config management)

Important Files Changed

Filename	Overview
numba_cuda/numba/cuda/np/arrayobj.py	Removed memcpy fast path in `_array_copy`, causing performance regression; added `constant_list` lowering
numba_cuda/numba/cuda/tests/cudapy/test_array_methods.py	Refactored to use `NRTEnablingCUDATestCase`, but redundant config management remains in `setUp`/`tearDown`
numba_cuda/numba/cuda/tests/cudapy/test_array_reductions.py	Added comprehensive tests for `median`, `percentile`, and `quantile`; redundant NRT config management

greptile-apps

Additional Comments (1)

numba_cuda/numba/cuda/tests/cudapy/test_array_reductions.py, line 25-36 (link)

logic: redundant config management - NRTEnablingCUDATestCase already manages self.old_nrt_setting and config.CUDA_ENABLE_NRT in its own setUp/tearDown

this creates duplicate state and could cause issues. remove the NRT-related lines:

_{7 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

greptile-apps · 2026-01-21T17:07:20Z

numba_cuda/numba/cuda/np/arrayobj.py

    assert rettype.layout in "CF"
-    if arytype.layout == rettype.layout:
-        # Fast path: memcpy
-        cgutils.raw_memcpy(
-            builder, dest_data, src_data, ary.nitems, ary.itemsize, align=1
-        )

-    else:
-        src_strides = cgutils.unpack_tuple(builder, ary.strides)
-        dest_strides = cgutils.unpack_tuple(builder, ret.strides)
-        intp_t = context.get_value_type(types.intp)
+    src_strides = cgutils.unpack_tuple(builder, ary.strides)
+    dest_strides = cgutils.unpack_tuple(builder, ret.strides)
+    intp_t = context.get_value_type(types.intp)

-        with cgutils.loop_nest(builder, shapes, intp_t) as indices:
-            src_ptr = cgutils.get_item_pointer2(
-                context,
-                builder,
-                src_data,
-                shapes,
-                src_strides,
-                arytype.layout,
-                indices,
-            )
-            dest_ptr = cgutils.get_item_pointer2(
-                context,
-                builder,
-                dest_data,
-                shapes,
-                dest_strides,
-                rettype.layout,
-                indices,
-            )
-            builder.store(builder.load(src_ptr), dest_ptr)
+    with cgutils.loop_nest(builder, shapes, intp_t) as indices:
+        src_ptr = cgutils.get_item_pointer2(
+            context,
+            builder,
+            src_data,
+            shapes,
+            src_strides,
+            arytype.layout,
+            indices,
+        )
+        dest_ptr = cgutils.get_item_pointer2(
+            context,
+            builder,
+            dest_data,
+            shapes,
+            dest_strides,
+            rettype.layout,
+            indices,
+        )
+        builder.store(builder.load(src_ptr), dest_ptr)


logic: removed memcpy fast path optimization when source and destination layouts match - this causes performance regression for same-layout copies

the original code had:

if arytype.layout == rettype.layout: # Fast path: memcpy cgutils.raw_memcpy(builder, dest_data, src_data, ary.nitems, ary.itemsize, align=1)

consider restoring the fast path for performance

brandon-b-miller and others added 23 commits October 14, 2025 08:26

basic test, bits and pieces of nrt needed

beeadd1

some progress

634e976

Refactor

9e12144

more reductions

c4d4abe

fix ufuncs

06226f2

Merge branch 'main' into vendor-test-array-reductions

2f48967

enable nrt

6611805

fixes

7bc54a0

pass

8f87a44

faster?

9969223

Merge branch 'main' into vendor-test-array-reductions

3ad3e1f

Merge branch 'main' into vendor-test-array-reductions

ddb0062

Apply suggestions from code review

398489b

Co-authored-by: Phillip Cloud <417981+cpcloud@users.noreply.github.com>

export

b58d757

basic

a7e24cc

add test that exhibits the failure

14026e8

implement fix

10f21fd

Merge branch 'fix-numpy-array-device-copy' into vendor-test-array-red…

51cf513

…uctions-2

updates

054041f

merge/resolve

7f5a647

move files, add NRTEnablingCUDATestCase

0595cb9

cleanup

108df98

more tests, buggy copy exposed again

dd1de26

brandon-b-miller changed the title ~~Vendor numpy median, percentile, and quantile reductions~~ Vendor numpy median, percentile, and quantile reduction tests Oct 31, 2025

brandon-b-miller added 5 commits November 4, 2025 04:49

partial list impl

5aa441a

merge/refactor

9e4ddfe

more tests

5ab95bc

Merge branch 'main' into vendor-test-array-reductions-2

ebb65ef

renaming

12ef058

gmarkall added the 2 - In Progress Currently a work in progress label Nov 18, 2025

brandon-b-miller added 2 commits December 11, 2025 11:53

merge/resolve

814f800

merge/resolve

ebfd572

brandon-b-miller added 3 - Ready for Review Ready for review by team and removed 2 - In Progress Currently a work in progress labels Jan 21, 2026

brandon-b-miller marked this pull request as ready for review January 21, 2026 17:03

greptile-apps bot reviewed Jan 21, 2026

View reviewed changes

brandon-b-miller added 2 - In Progress Currently a work in progress and removed 3 - Ready for Review Ready for review by team labels Jan 22, 2026

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Vendor numpy `median`, `percentile`, and `quantile` reduction tests #567

Vendor numpy `median`, `percentile`, and `quantile` reduction tests #567

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Greptile Summary

Confidence Score: 3/5

Important Files Changed

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