### What does this PR do?
**Type of change:** New example + new `modelopt.torch.fastgen` library
module.
Adds **DMD2 (Distribution Matching Distillation) for Qwen-Image** —
distilling the base model into a few-step (1–4) generator. Includes the
framework-agnostic `modelopt.torch.fastgen` loss library (DMD pipeline,
EMA, optional GAN discriminator) and a NeMo AutoModel–based training
example with a mock-data smoke config, a real-data config, and inference
/ export scripts.
**Noted**: the example script will be migrated to AutoModel repo
### Usage
```bash
# Mock-data wiring smoke — runs end-to-end with no dataset to prepare
torchrun --nproc-per-node=8 \
examples/diffusers/fastgen/dmd2_finetune.py \
--config examples/diffusers/fastgen/configs/dmd2_qwen_image_smoke.yaml
```
See `examples/diffusers/fastgen/README.md` for real-data training and
inference.
### Testing
Unit tests under `tests/unit/torch/fastgen/`; `pre-commit` /
code-quality clean.
### Before your PR is "*Ready for review*"
- Backward compatible?: ✅ (new, additive module)
- Followed `CONTRIBUTING.md` for any copied code / new deps: ✅
- New tests added?: ✅
- Updated Changelog?: N/A
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Adds a FastGen-based distillation framework (DMD2) with
student/fake-score training, EMA support, GAN discriminator branch,
inference pipeline, and export utilities.
* Qwen-Image integration with latent packing and feature-capture for
plugin-enabled pipelines.
* **Documentation**
* New README, example configs, and runnable example scripts for
Qwen-Image distillation and inference.
* **Tests**
* Comprehensive unit tests covering math parity, gradient routing,
plugins, hooks, EMA, and recipe setup.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Signed-off-by: Jingyu Xin <jingyux@nvidia.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
### What does this PR do?
Type of change: new feature <!-- Use one of the following: Bug fix, new
feature, new example, new tests, documentation. -->
- Add Conv3D implicit GEMM kernel with BF16 WMMA tensor cores and fused
NVFP4 activation quantization for video diffusion VAE layers
- Integrate into _QuantConv3d via QuantModuleRegistry — automatically
dispatched when NVFP4 quantization is applied to nn.Conv3d
- Move kernel from `experimental/conv/ to modelopt/torch/kernels/conv/`;
move tests to `tests/gpu/torch/quantization/kernels/`
### Testing
<!-- Mention how have you tested your change if applicable. -->
- Added test cases to measure the difference between cuDNN and our CUDA
implicit GEMM kernel
- Added an NVFP4 fake quantization test using CUDA code
### 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?: ✅ <!--- If ❌, explain why. -->
- If you copied code from any other sources or added a new PIP
dependency, did you follow guidance in `CONTRIBUTING.md`: ✅ <!---
Mandatory -->
- Did you write any new necessary tests?: ✅ <!--- Mandatory for new
features or examples. -->
- Did you update
[Changelog](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?:
✅ <!--- Only for new features, API changes, critical bug fixes or
backward incompatible changes. -->
### Additional Information
<!-- E.g. related issue. -->
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Per-backbone quantization/export in a single run with per-backbone
checkpoints and backbone-aware quant filters
* Configurable NVFP4 block-size via CLI/config; improved NVFP4 Conv3D
inference path and Wan 2.2 quantization support
* **Bug Fixes**
* Video-model calibration now respects extra params and forces video
decoding during calibration
* **Documentation**
* Added comprehensive Conv3D implicit‑GEMM kernel documentation; removed
experimental Conv3D prototype docs/benchmark
* **Tests**
* New Wan 2.2 quantization/export tests and expanded Conv3D/FP4 kernel
test coverage
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Signed-off-by: Jingyu Xin <jingyux@nvidia.com>
