Correct test_segmented_reduce.py::test_segmented_reduce #4197
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oleksandr-pavlyk
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Mar 19, 2025
… offsets To resolve NVIDIAgh-4197, use `cupy.cumsum` to accumulate over random partition sizes to form correct offsets sequence. Add assertions to verify that `offsets` is a non-decreasing sequence, and that its last element equals the size of the input array. Perform the test for several plausible offset data types.
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caugonnet
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Mar 25, 2025
* Fix logic in test_segmented_reduce, also test over different types of offsets To resolve NVIDIAgh-4197, use `cupy.cumsum` to accumulate over random partition sizes to form correct offsets sequence. Add assertions to verify that `offsets` is a non-decreasing sequence, and that its last element equals the size of the input array. Perform the test for several plausible offset data types. * Changes per PR review comments 1. Use `cupy.random` to draw random sample on GPU, rather than on CPU followed by a transfer 2. Use `cp.empty` to allocate output, rather than `cp.zeros`
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The test is meant to create partition of input array into random-size segments, call
segmented_reduceand verify against sequential calls tosumover segments.The test does not correctly form offsets associated with such partition. It samples random sizes from multinomial distribution, but fails to scan over these sizes, hence producing a sequence which is not guaranteed to be non-decreasing.
The test should be modified to perform meaningful acceptance testing.
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