Support for BharatGen's Param2MoE model architecture

[bhargav-patel-29]

What does this PR do?

This PR adds support for Param-2-17B-MoE-A2.4B, a large-scale Mixture-of-Experts (MoE) causal language model.

Param-2-17B-MoE-A2.4B uses a Hybrid Dense + MoE architecture with 17B total parameters while activating only 2.4B parameters per token, enabling high model capacity with efficient inference cost.

The model is pretrained from scratch with strong multilingual capabilities and particular emphasis on linguistic diversity and Indian language representation. It is released as a pretrained base model intended for downstream fine-tuning.

This PR introduces the following components:

• configuration_param2moe.py

  • Implements Param2MoEConfig
  • Defines model hyperparameters including transformer architecture, MoE routing configuration, number of experts, hidden sizes, and other initialization parameters.

• modeling_param2moe.py

  • Implements:
    • Param2MoEModel
    • Param2MoEForCausalLM
  • Includes hybrid transformer blocks with MoE routing and expert dispatch logic.
  • Supports causal language modeling and text generation workflows.

• __init__.py

  • Registers the model configuration and modeling classes to enable loading via:
    • AutoConfig
    • AutoModel
    • AutoModelForCausalLM

This integration enables seamless loading, inference, and downstream fine-tuning using standard Transformers APIs.

Fixes # (issue)

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Who can review?

Text models:
@ArthurZucker
@Cyrilvallez

[Rocketknight1]

Hi @bhargav-patel-29, thank you for the PR! Before we review, can you convert the PR to modular form by adding the changes in a modular file instead of a modeling file and then running make fix-repo to autogenerate the rest? Take a look at other recent PRs like Jais2 to see the structure, and the other stuff like auto mappings that a model PR needs: https://github.com/huggingface/transformers/pull/42684/changes

[github-actions]

[For maintainers] Suggested jobs to run (before merge)

run-slow: auto, param2moe

[github-actions]

View the CircleCI Test Summary for this PR:

https://huggingface.co/spaces/transformers-community/circle-ci-viz?pr=43888&sha=d46c70