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Jenny ChenandClaude Opus 4.8
e2c4d083d4
### What does this PR do? [Four Over Six](https://arxiv.org/pdf/2512.02010) PTQ implementation for weight-only quantization. Four Over Six was used to produce the Nemotron 3 Ultra NVFP4 checkpoint. Also updates the Ultra PTQ example in the launcher to use this new 4/6 config `huggingface/nvidia/Nemotron-3-Ultra-550B-A55B/ptq/ultra-nvfp4-46-max` ### Usage ```bash uv run launch.py --yaml examples/nvidia/NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16/megatron_lm_ptq.yaml --yes ``` ### Testing - [x] Unit tests pass - [x] Run launcher example ### Before your PR is "*Ready for review*" Make sure you read and follow [Contributor guidelines](https://github.com/NVIDIA/Model-Optimizer/blob/main/CONTRIBUTING.md) and your commits are signed (`git commit -s -S`). Make sure you read and follow the [Security Best Practices](https://github.com/NVIDIA/Model-Optimizer/blob/main/SECURITY.md#security-coding-practices-for-contributors) (e.g. avoiding hardcoded `trust_remote_code=True`, `torch.load(..., weights_only=False)`, `pickle`, etc.). - Is this change backward compatible?: ✅ / ❌ / N/A <!--- If ❌, explain why. --> - If you copied code from any other sources or added a new PIP dependency, did you follow guidance in `CONTRIBUTING.md`: ✅ / ❌ / N/A <!--- Mandatory --> - Did you write any new necessary tests?: ✅ / ❌ / N/A <!--- Mandatory for new features or examples. --> - Did you update [Changelog](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?: ✅ / ❌ / N/A <!--- Only for new features, API changes, critical bug fixes or backward incompatible changes. --> - Did you get Claude approval on this PR?: ✅ / ❌ / N/A <!--- Run `/claude review`. NVIDIA org members can self-trigger for complex changes; orthogonal to CodeRabbit. --> ### Additional Information <!-- E.g. related issue. --> <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **New Features** * Added NVFP4 Four‑Over‑Six (4/6) adaptive per‑block weight scaling and a configurable FP8 normalization option for FP4/FP8 quantization. * **Documentation** * Added PTQ recipes/presets and updated config docs to document FP8 max variants and the Four‑Over‑Six option. * **Tests** * Added unit and GPU tests validating 4/6 selection, normalization threading, scaling behavior, and reconstruction error checks. * **Chores** * Updated a PTQ pipeline example to use the NVFP4‑46‑max recipe and bumped a container image; minor project config tweak. <!-- end of auto-generated comment: release notes by coderabbit.ai --> --------- Signed-off-by: Jennifer Chen <jennifchen@nvidia.com> Signed-off-by: Jenny Chen <jennifchen@nvidia.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>