Files
Model-Optimizer/examples/speculative_decoding/distributed_generate
skierat c4129b6e03 Add Cosmos3 Nano DFlash multimodal training recipe (#2053)
### What does this PR do?

  Type of change: new example

Adds an end-to-end Cosmos3 Nano DFlash training recipe for multimodal
speculative decoding.

- Adds a notebook that prepares data, launches synthetic generation in
Slurm, trains a DFlash draft model, exports it, and provides a vLLM
smoke-test command.
- Adds PAI-Understanding, VQA v2, and multilingual prompt sharding and
distributed-generation helpers.
- Adds an atomic, multimodal-safe merge and conservative deduplication
flow.
- Extends the VLM data collator to handle structured image/video
messages, configurable visual bounds, and fixed DFlash sequence lengths.
- Hardens generation launch scripts and preserves truncated generated
responses.

  ### Usage

  ```bash
  cd examples/speculative_decoding/recipes

  export MODEL_PATH=/path/to/cosmos3-nano
export
PLAIN_TEXT_INPUT=/path/to/nemotron-chat-or-approved-user-data.jsonl

  jupyter lab train_dflash_cosmos3_nano.ipynb

  Run the notebook in order:

  1. Configure paths.
2. Prepare prompts on a CPU-only node and generate target completions in
a Slurm GPU allocation.
  3. Merge the four required sources and submit training.
  4. Export a saved checkpoint and run the vLLM deployment smoke test.

  ### Testing

- jq empty
examples/speculative_decoding/recipes/train_dflash_cosmos3_nano.ipynb
  - bash -n on the modified launch, worker, and recipe shell scripts.
- Ran a two-step Cosmos3 Nano DFlash Slurm smoke job; it completed and
wrote modelopt_state.pth.
- Not run: pytest
tests/unit/torch/speculative/plugins/test_hf_speculative_offline.py
(pytest is unavailable in the current environment).

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

  - Is this change backward compatible?: ✅
- 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?: ✅
  - Did you update CHANGELOG.rst?: N/A
  - Did you get Claude approval on this PR?: N/A

  ### Additional Information

Security follow-up required before marking ready: the notebook hardcodes
model.trust_remote_code=true and --trust_remote_code. Either
parameterize
this with a default of false, or obtain and document a security
exception.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added end-to-end multimodal workflows for dataset preparation,
distributed generation, result merging, training, export, and deployment
testing.
* Added support for image and video inputs, multiple dataset formats,
resumable JSONL generation, configurable serving, and parallel
processing.
* Added configurable prompt, media, token, sequence, temperature, and
tensor-parallel settings.
* **Bug Fixes**
* Improved truncated-response handling, assistant-label processing,
validation, health checks, cleanup, deduplication, media resolution,
atomic outputs, and failure reporting.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Slawomir Kierat <skierat@nvidia.com>
2026-08-14 21:20:17 +08:00
..
2025-06-05 13:24:07 -07:00