The Stan transpiler (from Stan to C++ and beyond).
C-Rank Grade: A (Welcoming) - 62/100
External PR Merge Rate: 74%
Response Time: -
First Timer Success: 50%
stan-dev/stanc3 has a recorded first-timer success rate of 50.0%. Repositories ranked A typically provide actionable feedback during code reviews and actively nurture new community contributors.
Maintainers in stan-dev/stanc3 respond to incoming external pull requests in approximately 0.0 hours on average. Keeping PRs focused on single tasks and ensuring tests pass helps maintainers review faster.
The C-Rank™ system evaluates GitHub projects on a 0–100 scale using real data: PR merge rates, review turnaround time, active maintainer presence, and first-time contributor success. A score of 62.1 places stan-dev/stanc3 in the A tier.
The external contributor pull request merge rate for stan-dev/stanc3 is 74.1%, based on public PR activity from non-core contributors.
stan-dev/stanc3 currently has 2 active issue(s) tagged with beginner-friendly labels like "good first issue", "beginner", or "up-for-grabs".
Growing OCaml project in stan-dev/stanc3 welcoming community pull requests and bug fixes.
Average Response Latency
Tracks hours until a maintainer leaves a review, comment, or PR response.
External Acceptance Rate
Percentage of community pull requests successfully merged into main.
First PR Conversion
Rate at which developers submitting their first repository PR succeed.
Show contributors that your repository actively reviews and merges external pull requests.
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Historical health & responsiveness evolution
External PR acceptance
First PR success rate
50% receive response in
90% receive response in
Maintainer review activity heatmap & prime window prediction
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Detected: UTC
Maintainers are most responsive around 18:00 UTC (18:00 UTC in your timezone). Recommended submission window is Wednesday - Friday from 17:00 to 21:00 UTC (17:00 - 21:00 UTC local).
Maintainer Strategy: Maintainer Sweet Spot: PRs under 150 lines merge in ~16 hours (93% approval). Large PRs (>500 lines) take ~115 hours (33% approval). Keep your diff compact for rapid review.
Problem Right now each of our optimization passes uses the same symbol generator which builds sym1__, sym2__, sym3__, symN__. When there is a change in the optimizer you end up with a bunch of sym*__ changes and it is very hard to grep and grock when and why those changes happened. Possible Answer We should have a symbol name generator that operates per optimization. So for each pass we would generate sym{PASS_NAME}1__, ..., sym{PASS_NAME}N__. I think this will make it easier to read what caused a change and where.
See #1674 for an initial attempt. Thanks to @sims1253 for the suggestion There are several functions that historically duplicated work and now can be done in a single call returning a tuple. These were primarily added in stan-dev/math#2931: qr: replaces calls to qr_Q/qr_R qr_thin: replaces calls to qr_thin_Q/qr_thin_R eigendecompose_sym: replaces calls to eigenvalues_sym/eigenvectors_sym eigendecompose: replaces calls to eigenvalues/eigenvectors complex_schur_decompose: replaces calls to complex_schur_decompose_t/complex_schur_decompose_u svd: replaces calls to svd_U/svd_V csr_extract : replaces calls to csr_extract_u/csr_extract_v/csr_extract_w The proposal is to add a small optimization which detects cases where these are called one after the other and rewrite them to use the combined version. It may also be useful to separately flag a warning for models where the older functions are both called on the same thing.
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When evaluating whether to contribute to stan-dev/stanc3, response velocity and maintainer engagement are crucial. GetMerged continuously tracks pull request trajectories, first-comment latency, and code review rounds to help developers avoid submitting pull requests to backlogged repositories.
Currently, maintainers of stan-dev/stanc3 acknowledge new external contributions in approximately -. Out of all submitted pull requests from non-core authors in the last 180-day window, 74.1% were successfully merged into the primary branch.
stan-dev/stanc3 has a recorded first-timer success rate of 50.0%. Repositories ranked Welcoming typically provide actionable feedback during code reviews and actively nurture new community contributors.
The initial maintainer response time averages ~-. Keeping PRs scoped to single concerns and ensuring CI checks succeed will optimize review turnaround.
The C-Rank™ index scores repositories on a 0 to 100 scale using an objective formula: external PR merge rates, initial response speed, active maintainer count, and first-time contributor retention. A score of 62.1 places stan-dev/stanc3 in the Welcoming tier.
The external pull request merge rate is 74.1%. GetMerged isolates non-core community contributions so external developers get an accurate benchmark of PR acceptance probability.
Yes, stan-dev/stanc3 currently has 2 active issue(s) tagged with beginner-friendly labels. You can inspect these directly from the repository issues tab.
All metrics displayed for stan-dev/stanc3 are automatically retrieved via the public GitHub API and recalculated daily. Insider pull requests submitted by repository owners or organization members are excluded from merge rate calculations to preserve objective external contributor statistics.