Merge Models with Non-Standard Architectures (e.g., Multimodal Models)

[ElliotStein]

This update extends merge capabilities to models without predefined architecture JSON files, enabling support for models with non-standard architectures such as multimodal models.

Key Changes:

• Automatic Architecture Info Creation: For models without an architecture JSON specification in /_data/architectures, an ArchitectureInfo class is automatically generated by reading parameter names from the saved model.
  - Efficiency Note: Reading parameter names is significantly faster for models saved in .safetensors format compared to .bin.
• Parameter Organization: While pre/post weights aren’t explicitly segregated, parameters are grouped into layers based on the pattern .{integer}. in parameter names.
• Architectural Compatibility Requirement: Currently only supports merging models with identical architectures.

Modifications to Core Functionality:

• get_architecture_info: Now returns False and raises a warning if it fails, rather than raising an error outright.

Additional Updates:

• Minor bug fixes to testing and GPT-2 configuration.

This change does not impact functionality for models with predefined architecture JSON specifications (i.e., all currently supported merges).