stan-dev / stan-dev/stan

Too loose ASSERT_NEAR and wrong test values in compute_potential_scale_reduction_test.cpp

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C++
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Description

Description:

I have tried reducing the accepted error in ASSERT_NEAR from 1 to 1e-4, but then the tests failed for ComputeRhat.compute_potential_scale_reduction and ComputeRhat.compute_potential_scale_reduction_convenience. Upon inspection, the test values are the same as for compute_split_potential_scale_reduction and compute_split_potential_scale_reduction_convenience, for which the corresponding functions output different values.

Current Version:

v2.34.1

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Research direction

Open compute_potential_scale_reduction_test.cpp and compare the expected values and ASSERT_NEAR tolerances for the regular and split potential scale reduction tests. Run ComputeRhat.compute_potential_scale_reduction and ComputeRhat.compute_potential_scale_reduction_convenience, along with their split counterparts; done means the expected values and tighter tolerance reflect each function's output and all four tests pass.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
testing-qa
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
50/100

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