fix(lammps): support 2025 Kokkos API

[njzjz-bot]

Summary

Backport 0002-support-lammps-2025-kokkos-api.patch from conda-forge/deepmd-kit-feedstock@d02138263b0b30629fe28c68c8bcecc2b8644513.

Support both the LAMMPS 22Jul2025 Kokkos API and newer LAMMPS releases by selecting the appropriate reverse-communication buffer and per-atom energy accumulator types from LAMMPS_VERSION_NUMBER.

Validation

• Four-file backport matching the feedstock patch.
• Split from fix: backport conda-forge build fixes #5985 so the compatibility change can be reviewed independently.
• Full build is left to upstream CI.

Agent: ChatGPT
Model: GPT-5.6 Sol

Summary by CodeRabbit

• Compatibility

  • Improved support across multiple LAMMPS versions for Kokkos-based DeepMD and DPA-4-spin simulations.
  • Updated reverse communication and per-atom energy handling to use version-compatible data formats.

• Bug Fixes

  • Resolved compatibility issues that could affect reverse communication and energy accumulation across LAMMPS releases.
  • Preserved existing force, magnetic-force, and virial calculation behavior.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: f6de0aa4-9468-4e7e-8381-76e52b2a54b7

📥 Commits

Reviewing files that changed from the base of the PR and between a119bd0 and 044d75b.

📒 Files selected for processing (2)

• source/lmp/pair_deepmd_kokkos.h
• source/lmp/pair_dpa4spin_kokkos.h

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

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📝 Walkthrough

Walkthrough

Changes

Kokkos compatibility updates

Layer / File(s)	Summary
DeepMD compatibility types and methods source/lmp/pair_deepmd_kokkos.h, source/lmp/pair_deepmd_kokkos.cpp	DeepMD selects communication-buffer and per-atom energy accumulator types by LAMMPS version. Reverse-communication declarations and definitions use the buffer alias.
DPA4Spin compatibility types and methods source/lmp/pair_dpa4spin_kokkos.h, source/lmp/pair_dpa4spin_kokkos.cpp	DPA4Spin selects communication-buffer and per-atom energy accumulator types by LAMMPS version. Reverse-communication definitions use the buffer alias.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 044d7

This PR updates LAMMPS Kokkos compatibility in a localized set of files without any identified merge-blocking correctness, security, availability, or deployment risk; no actionable merge-blocking risk remains beyond normal checks and review.

Suggested reviewers: outisli

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding support for the 2025 LAMMPS Kokkos API.
Docstring Coverage	✅ Passed	Docstring check was indeterminate for this PR — some files could not be analyzed in time. Not blocking.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.84%. Comparing base (8cfd46e) to head (044d75b).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5987      +/-   ##
==========================================
- Coverage   79.10%   78.84%   -0.26%     
==========================================
  Files        1105     1105              
  Lines      130981   130981              
  Branches     4771     4765       -6     
==========================================
- Hits       103609   103271     -338     
- Misses      25686    26027     +341     
+ Partials     1686     1683       -3     

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[OutisLi]

The compatibility cutoff is incorrect. Both headers select the legacy tdual_xfloat_1d reverse-communication signature and legacy energy accumulator types for every LAMMPS version before 20260704, but the official patch_10Sep2025 release already uses DAT::tdual_double_1d in KokkosBase and provides ttransform_kkacc_1d / t_kkacc_1d; the same APIs remain in patch_10Dec2025, patch_11Feb2026, and patch_30Mar2026. Consequently those releases take the wrong branch, and the override declarations do not match the base virtual functions, causing compilation to fail for both deepmd/kk and dpa4spin/kk. Please use the actual API-introduction boundary (the released-tag evidence points to 20250910) and validate at least stable_22Jul2025_update5, patch_10Sep2025, and the current LAMMPS release.

[njzjz]

Addressed in 044d75b4e. Both Kokkos compatibility checks now use the actual API boundary, LAMMPS_VERSION_NUMBER < 20250910, so stable_22Jul2025_update5 selects the legacy buffer/accumulator types while patch_10Sep2025 and newer select DAT::tdual_double_1d, ttransform_kkacc_1d, and t_kkacc_1d.

I validated the combined #5987, #5989, and #5988 changes with PKG_PLUGIN=ON, PKG_KOKKOS=ON, and DEEPMD_LAMMPS_KOKKOS=ON against:

• stable_22Jul2025_update5
• patch_10Sep2025
• patch_20Aug2026 (current tag; its LAMMPS version header reports 4 Jul 2026)

Both pair_deepmd_kokkos.cpp and pair_dpa4spin_kokkos.cpp compiled successfully in all three builds. Each resulting plugin also loaded successfully under Kokkos and plugin list reported all six Kokkos aliases.

Coding agent: Codex
Codex version: codex-cli 0.149.0
Model: gpt-5.6-sol
Reasoning effort: xhigh