1.7 KiB
Root-channel parity diagnostic
This is a read-only diagnostic, not a replacement acceptance gate. It requires a
caller-admitted GPU and the unchanged checkout containing
test_channel_root_gpu.py. It does not run unrelated body/Jet tests.
From the checkout, run:
python /path/to/channel_parity_diagnostic/discover.py --checkout "$PWD" --output /new/evidence/directory
Discovery invokes only the original test_uniform_matched_root method, with its
original loops and exact assertion. It stops at the first assertion failure,
extracts the configuration and arrays from that original traceback, saves the
failure verbatim, and serially starts replay.py in a fresh Python process.
The original failure remains a failure: exit 1 means the assertion was captured,
even if the targeted replay succeeds or does not reproduce it. Exit 2 means the
original test did not reproduce the failure; exit 3 means a different assertion
failed and no configuration was guessed. Other errors are retained and raised.
Targeted replay compiles only the uniform and one failed blocked configuration, serially, caching the two modules. It saves PTX and compiler metadata, all numeric and bit-only mismatches with coordinates/hex/ULPs at each step, first numeric divergence arrays, same-input localization, and comparison against the original multistep call. Signed-zero-only bit changes cannot trigger the first numeric divergence. The final replay consistency checks establish whether the one-step observation sequence agrees with the original call structure.
Outputs retain the original source revision and gate SHA256. No source, assertion, tolerance, compiler flags, collision math, or kernel scheduling is changed. Findings must be reviewed before any production fix or gate change.