⚡ Move _resize_sd Out of Inner Loop

[igor-holt]

What: The _resize_sd function was defined inside the sample_single_block function, which is called inside a loop. This change moves the definition to the module level.

Why: Defining a function inside a loop creates a new function object and closure every time. In large models with thousands of blocks, this adds unnecessary Python overhead during JAX tracing. Moving it out improves code efficiency and clarity.

Measured Improvement:

• Baseline tracing time (1000 blocks): ~24.6s
• Optimized tracing time (1000 blocks): ~24.5s
• Execution time: ~0.009s (unchanged)

While the measured improvement in tracing time is negligible (due to JAX tracing overhead dominating), the change eliminates redundant operations and improves code structure.

---

PR created automatically by Jules for task 6386688111311676134 started by @igor-holt

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[gemini-code-assist]

Summary of Changes

Hello @igor-holt, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the thrml/block_sampling.py file by extracting the _resize_sd helper function from within the sample_single_block function. The primary goal is to optimize JAX tracing performance and improve code structure by avoiding the repeated creation of the function object and its closure during loop iterations, even if the measured performance gain is negligible.

Highlights

• Function Relocation: The _resize_sd function was moved from being defined inside sample_single_block to the module level, preventing its re-creation on each loop iteration.
• Improved Efficiency: This change eliminates redundant function object and closure creation within a loop, aiming to improve JAX tracing efficiency, particularly for large models, though measured improvements were minimal.
• Code Clarity: The refactoring enhances code clarity by defining a utility function at a higher, more appropriate scope.

Changelog

• thrml/block_sampling.py
  • Moved the _resize_sd function definition from inside sample_single_block to the module level.
  • Updated the call to _resize_sd to use the new module-level function, passing n_nodes as an argument.
  • Imported Any from the typing module.

Activity

• PR created automatically by Jules for task 6386688111311676134, started by @igor-holt.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request refactors the _resize_sd function by moving it from inside the sample_single_block function to the module level. This is a good change that improves code structure and clarity. By making _resize_sd a pure, module-level function, the code becomes more modular and easier to reason about. While the PR description mentions performance, the primary benefit here is the structural improvement, as a lambda function is still created within the loop where sample_single_block is called. Overall, this is a positive change for code quality and I approve of the changes.