Make seeded runs reproducible across releases and say how they depend on the backend

Open
  • Is something wrong?
#15 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
55/100
Issue type
Feature
Clarity
Clearly specified
Activity status
Active
Tech stack
python, rust
Domain
backend, documentation, testing

Research direction

Start by locating the run implementation and its StdRng usage, then check the README, run docstrings, and the FAQ entry named in the issue. Read how backend="auto" selects its probability precision and inspect the existing seeded-run tests. Done means the generator is explicitly versioned, a fixed-seed test pins exact counts, and all three documentation locations describe reproducibility by engine version and backend.

Written by the indexing model from the issue text.

Description

enhancement
What you want to do

run(seed=42) is documented as giving "repeatable counts", but:

  • StdRng does not guarantee the same random stream across rand versions, so counts may change
    after a dependency update;
  • with backend="auto", a machine with a GPU and one without sample from different probabilities
    (f32 vs f64), so the same seed can give different counts.
Implementation notes
  • Replace StdRng with an explicitly versioned generator such as rand_chacha::ChaCha8Rng or
    ChaCha20Rng, and add a test that pins the exact counts for a fixed seed, so a change is caught.
  • Update the README, run docstrings and the FAQ entry "Will the same seed give the same counts?"
What it could look like
No API change. The docs say: "the same seed gives the same counts with the same qsengine
version and backend".
Contributing
  • I would like to open a pull request for this (see CONTRIBUTING.md).
Dominant language
Rust
Stars
1
Forks
0
Avg merge
12m
Merged PRs (30d)
4

Getting set up

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from kaiwave/qsengine

All issues in kaiwave/qsengine

Similar issues

More Rust issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.