Chenjie LuoandClaude Opus 5 9220fac053 [NVBug: 6563509] Drop Phi-3-vision / Phi-4-multimodal PTQ support (#2115)
### What does this PR do?

Type of change: Deprecation

Resolves [NVBug 6563509](https://nvbugspro.nvidia.com/bug/6563509),
where
`hf_ptq.py` on Phi-4-multimodal-instruct died with
`RuntimeError: Tensor.item() cannot be called on meta tensors`.

The crash is real but not fixable on our side, and it is not the reason
the model
is unusable. Phi-4-multimodal's bundled remote code predates
Transformers v5 and
does not load on **any** version in our supported range
(`transformers>=4.57,<5.15`):

| Blocker | Where |
|---|---|
| `peft.get_peft_model` reads `prepare_inputs_for_generation`, gone
since transformers 4.52 dropped `GenerationMixin` from `PreTrainedModel`
| `modeling_phi4mm.py:1959` |
| `_tied_weights_keys` declared as a list; Transformers 5.x calls
`.keys()` on it in `post_init` | `modeling_phi4mm.py:1937` |
| `int(torch.tensor(...))` in `__init__`, which cannot run on a meta
device — the reported crash | `speech_conformer_encoder.py:1435` |

The model card pins `transformers==4.48.2` / `peft==0.13.2`, so there is
no
overlap with our floor and nothing on our side can bridge it. The model
is
therefore dropped rather than worked around.

**Phi-3-vision is dropped alongside it because it is the older,
superseded model
in the same family** — with its successor unsupportable there is no
reason to
keep carrying the predecessor. This is a product-scope call, not a
separate
compatibility finding: Phi-3-vision shares the list-valued
`_tied_weights_keys`
defect (`modeling_phi3_v.py:1214`) and so is likewise broken on
Transformers 5.x,
but it does **not** hit the `peft` blocker, and it was not re-verified
on 4.57.
Per the 0.46 changelog we have already bumped the floor to 4.57 and
noted that
"Transformers 4.x support will be dropped in a future release", so any
remaining
window closes on its own. Same reasoning already applied to VILA / NVILA
in this
release.

**Removed**

- the support-matrix row in `examples/hf_ptq/README.md`
- `"Phi4MMForCausalLM": "phi4mm"` from `MODEL_NAME_TO_TYPE`
- the multimodal-detection heuristics that only ever matched these two —
`vision_lora`, `audio_processor`, `embd_layer.image_embd_layer`, and the
  `phi4mm` model-type check — in both `is_multimodal_model` and
  `_is_multimodal_config`
- the `Phi3Image` / `PhiImage` exclusions in `is_embedding`
- the phi4mm input-mode warning in `hf_ptq.py`
- `modelopt_recipes/huggingface/phi4mm/` and its references in
  `modelopt_recipes/ptq.md`

**Not changed:** the device-map sizing path (meta-device skeleton,
`infer_auto_device_map`, and the `--gpu_max_mem_percentage` cap) keeps
its
original behavior. That cap is wanted exactly where it already fires —
when the
model is already offloading to CPU, where it costs little and the
headroom is
required. With the affected checkpoints removed, there is no supported
model
that trips the meta-device build, so there is nothing to work around
here.

Text-only **Phi-3/Phi-4** and **Phi-3.5-MoE** are natively supported by
transformers and are untouched.

### Testing

On H200, `nvcr.io/nvidia/tensorrt-llm/release` (torch 2.12, transformers
5.5.4),
against the real checkpoint:

- **Version matrix** (vanilla transformers, no modelopt) — Phi-4-MM
loads at
4.48.2 / 4.49.0 / 4.50.0 / 4.51.3 and fails at 4.53.3 / 4.56.2 / 4.57.1
  (`AttributeError: 'Phi4MMModel' object has no attribute
'prepare_inputs_for_generation'`) and at 5.5.4 (meta-init, then
tied-keys).
  This is what establishes that no supported version works.
- `tests/examples/hf_ptq/test_example_utils.py` — 28 passed.
- **Sweep**: `tests/examples/hf_ptq` + `tests/unit/torch/export` —
failure set
identical to the pre-change tree (GPU/model-dependent `test_vlm_ptq`,
plus
`test_quant_aware_conversion` scoped-mapping tests), so none are
introduced
  here.
- `pre-commit` clean on all changed files, including recipe validation.

### Before your PR is "*Ready for review*"

- Is this change backward compatible?: ❌ — PTQ for Phi-3-vision and
  Phi-4-multimodal is removed, along with the `huggingface/phi4mm/ptq/*`
recipes. Phi-4-multimodal is already unloadable on every supported
transformers
version, so no working workflow regresses; Phi-3-vision is a deliberate
scope
  removal as its superseded predecessor.
- If you copied code from any other sources or added a new PIP
dependency, did you follow guidance in `CONTRIBUTING.md`: N/A
- Did you write any new necessary tests?: N/A — this is a deletion; the
existing
`test_get_model_*` / `test_resolve_init_config_*` tests are unchanged
and still
  pass.
- Did you update
[Changelog](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?:
✅
- Did you get Claude approval on this PR?: ❌ — not yet run.

### Additional Information

Two related references were left in place deliberately; say the word and
I'll
fold them in:

- `tests/examples/hf_ptq/test_deploy.py` still deploys the
already-published
`nvidia/Phi-4-multimodal-instruct-{NVFP4,FP8}` checkpoints. Those
artifacts
exist and serve fine; this PR only removes the ability to *produce*
them.
- `examples/torch_onnx/README.md` still lists Phi-4-multimodal-instruct.
That
is a separate ONNX pipeline that does not go through `get_model()` and
was not
  tested here.

Earlier revisions of this branch also reworked the device-map sizing so
the
meta-tensor crash could not occur. That was reverted in 701180ed6: the
guard is
correct as written, and every alternative either changed behavior for
models that
fit today or moved the guard somewhere it does not belong, for a crash
that only
ever affected the checkpoints this PR removes.

---------

Signed-off-by: Chenjie Luo <chenjiel@nvidia.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-10 23:22:23 +00:00
…
…

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NVIDIA Model Optimizer

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NVIDIA Model Optimizer (referred to as Model Optimizer, or ModelOpt) is a library comprising state-of-the-art model optimization techniques including quantization, pruning, Neural Architecture Search (NAS), distillation, speculative decoding and sparsity to accelerate models.

[Input] Model Optimizer currently supports inputs of a Hugging Face, PyTorch or ONNX model.

[Optimize] Model Optimizer provides Python APIs for users to easily compose the above model optimization techniques and export an optimized quantized checkpoint. Model Optimizer is also integrated with NVIDIA Megatron-Bridge, Megatron-LM and Hugging Face Accelerate for training required inference optimization techniques.

[Export for deployment] Seamlessly integrated within the NVIDIA AI software ecosystem, the quantized checkpoint generated from Model Optimizer is ready for deployment in downstream inference frameworks like SGLang, TensorRT-LLM, TensorRT, or vLLM. The unified Hugging Face export API now supports both transformers and diffusers models.

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Techniques

Technique Description Examples Docs
Post Training Quantization Compress model size by 2x-4x, speeding up inference while preserving model quality! [HF LLMs / VLMs] [Megatron-Bridge LLMs / VLMs] [Diffusers] [ONNX] [Windows] [docs]
Quantization Aware Training / Distillation Refine accuracy of quantized models even further with a few training steps! [Hugging Face] [Megatron-Bridge] [docs]
Pruning Reduce your model parameters or memory footprint and accelerate inference by removing unnecessary weights! [General] [Megatron-Bridge]
Distillation Reduce deployment model size by teaching small models to behave like larger models! [Hugging Face] [Megatron-Bridge] [Megatron-LM] [docs]
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Sparsity Efficiently compress your model by storing only its non-zero parameter values and their locations [Hugging Face] [docs]

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Model Support Matrix

Model Type Support Matrix
LLM / VLM Quantization View Support Matrix
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Citation

If you use NVIDIA Model Optimizer in your research, please cite it as follows:

@misc{nvidia-modelopt,
  author       = {{NVIDIA Corporation}},
  title        = {{NVIDIA Model Optimizer}},
  howpublished = {\url{https://github.com/NVIDIA/Model-Optimizer}},
  year         = {2024--2026},
  note         = {GitHub repository}
}

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