MilesCranmer/PySR: v2.0.0a2

Miles Cranmer; Dhananjay Ashok; tttc3; MilesCranmerBot; William Booth-Clibborn; Ward K Harold; wkharold; Johann Brehmer; William Booth-Clibborn; Mark Kittisopikul; Dilum Aluthge; Saurav Maheshkar; Shah Mahdi Hasan; Anubhav Kamal; Arthur Grundner; BrotherHa; DeepSource Bot; Ho Fung Tsoi; Hongyu Wang; Ilya Orson; Digvijay (Jay) Wadekar; LionessOfCintra; Manuel Morales; Miguel Crispim Romao; Paulo Montero Camacho; Raúl Peralta Lozada

doi:10.5281/zenodo.20225161

Published May 16, 2026 | Version v2.0.0a2

Software Open

MilesCranmer/PySR: v2.0.0a2

1. University of Cambridge
2. Loughborough University
3. Scott Logic
4. Qualcomm AI Research
5. @JaneliaSciComp
6. Brown University; Pumas-AI
7. @deepsourcelabs
8. University of Pennsylvania
9. Beihang University
10. Imperial College London
11. UT Austin
12. Peng Cheng Laboratory

What's Changed

Core PySR / Backend

Automated update to backend: v2.0.0-alpha.9 by @github-actions[bot] in https://github.com/MilesCranmer/PySR/pull/1132
fix: torch export with constant arguments by @MilesCranmer in https://github.com/MilesCranmer/PySR/pull/1058
fix: normalize DataFrame column spaces in predict by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1136
feat: raise friendly error when loss_function has elementwise signature by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1138
fix: warn on elementwise loss probe mismatch by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1184

<details> <summary>Backend changes from SymbolicRegression.jl v2.0.0-alpha.8 to v2.0.0-alpha.9</summary>

PySR v2.0.0a2 updates the Julia backend from SymbolicRegression.jl v2.0.0-alpha.8 to v2.0.0-alpha.9.

Backend release: https://github.com/MilesCranmer/SymbolicRegression.jl/releases/tag/v2.0.0-alpha.9

Full backend changelog: https://github.com/MilesCranmer/SymbolicRegression.jl/compare/v2.0.0-alpha.8...v2.0.0-alpha.9

Backend functionality and compatibility

merge: integrate PR #515 changes by @MilesCranmerBot in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/540
Add SymbolicUtils v4 compatibility by @MilesCranmerBot in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/542
Restore accidentally dropped Enzyme mention in docs by @wsmoses in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/537
ci: allow-fail enzyme integration group by @MilesCranmerBot in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/544

Backend tests and CI

Refactor test suite into projects by @MilesCranmer in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/524
test: split up mlj/templates by @MilesCranmer in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/525
style: update to formatter version 2 by @MilesCranmer in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/504
chore(deps): bump actions/setup-node from 4 to 5 by @dependabot[bot] in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/503
chore(deps): bump actions/setup-node from 5 to 6 by @dependabot[bot] in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/516
chore(deps): bump actions/upload-artifact from 4 to 5 by @dependabot[bot] in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/519
chore(deps): bump actions/download-artifact from 5 to 6 by @dependabot[bot] in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/520
chore(deps): bump actions/cache from 4 to 5 by @dependabot[bot] in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/529

Backend documentation

docs: add language picker by @MilesCranmer in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/512
docs: generate favicon from logo by @MilesCranmer in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/513

Backend new contributors

@MilesCranmerBot made their first contribution in https://github.com/MilesCranmer/SymbolicRegression.jl/pull/540

</details>

Packaging / Release / Dependencies

chore(deps): allow pandas <4.0.0 by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1129
ci: add release-please bootstrap for master by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1162
ci: publish PyPI from release-please on master by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1169
fix: keep release-please manifest on released prerelease by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1185
chore: prepare PySR 2.0.0a2 release by @MilesCranmer in https://github.com/MilesCranmer/PySR/pull/1189

CI / Testing / Automation

Create slurm unit tests + refactor to docker buildx bake by @MilesCranmer in https://github.com/MilesCranmer/PySR/pull/1111
ci: fix upper bound python for jax compat by @MilesCranmer in https://github.com/MilesCranmer/PySR/pull/1112
ci: avoid dependabot-only failures in conda/docker by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1130
Make backend-update PR branches version-specific by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1155
fix: trigger CI for backend update PRs by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1158
ci: fix backend bump automation by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1166

Documentation / Website / Papers

Switch docs to vitepress by @MilesCranmer in https://github.com/MilesCranmer/PySR/pull/1056
Paper PR workflow: sync/resize images to PySR_Docs by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1118
ci(papers): PNG output + alpha flatten + ~300KB target by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1119
fix(ci): paper-image bot updates PR comment + stable URLs by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1120
fix: relax papers.yml validator for PySR_Docs image URLs by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1122
Adding a recently published paper that used PySR by @paulomontero in https://github.com/MilesCranmer/PySR/pull/1098
Add paper: Learning Microstructure in Active Matter by @luna026 in https://github.com/MilesCranmer/PySR/pull/1107
Added Symbolic Regression for lithium-ion battery paper information by @anubhavkamal in https://github.com/MilesCranmer/PySR/pull/1074
Update papers.yml (duplicate of #1148) by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1156
Added a paper to the research showcase page by @MilesCranmerBot in https://github.com/MilesCranmer/PySR/pull/1172

Dependency / Workflow Maintenance

chore(deps): bump actions/checkout from 4 to 6 by @dependabot[bot] in https://github.com/MilesCranmer/PySR/pull/1086
chore(deps): bump peter-evans/create-pull-request from 7 to 8 by @dependabot[bot] in https://github.com/MilesCranmer/PySR/pull/1097
chore(deps): bump actions/cache from 4 to 5 by @dependabot[bot] in https://github.com/MilesCranmer/PySR/pull/1099
chore(deps): bump actions/setup-node from 4 to 6 by @dependabot[bot] in https://github.com/MilesCranmer/PySR/pull/1062
chore(deps): bump docker/setup-qemu-action from 3 to 4 by @dependabot[bot] in https://github.com/MilesCranmer/PySR/pull/1147
[pre-commit.ci] pre-commit autoupdate by @pre-commit-ci[bot] in https://github.com/MilesCranmer/PySR/pull/1039

New Contributors

@paulomontero made their first contribution in https://github.com/MilesCranmer/PySR/pull/1098
@luna026 made their first contribution in https://github.com/MilesCranmer/PySR/pull/1107
@anubhavkamal made their first contribution in https://github.com/MilesCranmer/PySR/pull/1074

Full Changelog: https://github.com/MilesCranmer/PySR/compare/v2.0.0a1...v2.0.0a2

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