Hybrid delta tracking - #4044

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nuclearkevin wants to merge 99 commits into

openmc-dev:developfrom

nuclearkevin:hybrid_tracking

Commits on Aug 3, 2026

Squash delta tracking commits.
nuclearkevin
committed
19222b0
Fix non-vacuum BCs.
nuclearkevin
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d33311b
Make non-vacuum BCs more robust.
nuclearkevin
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7c79feb
Allow for the import of majorant cross sections from CSV files.
nuclearkevin
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b924e5b
Missing setting.
nuclearkevin
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f40826c
Turn ptable sampling on for delta tracking.
nuclearkevin
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598e651
Begin majorant refactor.
nuclearkevin
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a771e62
Finish the "new" majorant implementation.
nuclearkevin
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87365cd
Better error messages.
nuclearkevin
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47c9b14
Fix issues with URR cross sections. Make error messages better
nuclearkevin
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9fc34a2
Prep for photon majorants.
nuclearkevin
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3c09dd8
Photon majorants & delta tracking for photon transport.
nuclearkevin
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67fe761
Errors for settings unsupported by delta tracking (for now).
nuclearkevin
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2e0548c
Compute majorants for all materials contained in a universe.
nuclearkevin
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e38d6d9
Fix delta tracking photon loop.
nuclearkevin
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8fe2416
Minor changes.
nuclearkevin
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423020d
Fix bug with universe majorants & reset majorants when finalizing a simulation.
nuclearkevin
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ce10cd4
Support distrib densities.
nuclearkevin
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00c34ee
Rename delta tracking functions.
nuclearkevin
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df68730
Support delta tracking with a shared secondary bank.
nuclearkevin
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90cecee
Remove CSV majorant cross sections.
nuclearkevin
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a8bd272
Revert to most conservative URR treatment.
nuclearkevin
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633d85b
Honestly, I don't know anymore...
nuclearkevin
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68c4ca4
Refactor history-based delta tracking to prepare for event-based.
nuclearkevin
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f50c4c7
First cut of event-based transport. Works for neutrons
nuclearkevin
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6937a76
Fixes for event-based delta tracking photon transport.
nuclearkevin
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6bb971f
More shuffling, add some extra division comments.
nuclearkevin
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8a2de34
Remove unnecessary cross section calculation event on particle initialization.
nuclearkevin
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a9be6f2
Forgot the coord reset.
nuclearkevin
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afb058e
Use FP_REL_PRECISION when advancing to boundaries.
nuclearkevin
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9bb0a34
Fix grid lookup.
nuclearkevin
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21ca364
Fix majorants, again...
nuclearkevin
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4d1c5b4
Remove unused code.
nuclearkevin
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80100d7
More cleanup.
nuclearkevin
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c08de75
More cleanup.
nuclearkevin
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23bb494
URR fix.
nuclearkevin
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5552e72
Have majorants conform to OpenMC's indexing approach. Also add a timer for majorant construction.
nuclearkevin
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5b4b97f
Remove ascii file writes.
nuclearkevin
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c026a50
Pretty formatting.
nuclearkevin
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3d0d7bf
Restrict delta tracking tallies to collision estimators.
nuclearkevin
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3783ba7
Remove unnecessary coord reset.
nuclearkevin
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5f51433
Clean up combined estimate for k.
nuclearkevin
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4051e0f
Clean up majorant and remove random duplicate code.
nuclearkevin
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09589e2
Shouldn't need this going into a boundary crossing.
nuclearkevin
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885343a
Remove more duplicate flagging.
nuclearkevin
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f12880b
More cleanup.
nuclearkevin
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15d4406
Round trip delta_tracking alongside the majorant build time in the SP.
nuclearkevin
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3dd9fa2
Remove event limit.
nuclearkevin
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4a6bf68
Delta tracking theory.
nuclearkevin
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df65464
Test round tripping the delta tracking setting.
nuclearkevin
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833e42f
Fix distributed density majorant bug.
nuclearkevin
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16398b2
More majorant fixes.
nuclearkevin
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0362c07
Test for distributed densities with delta tracking.
nuclearkevin
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9d10120
Add history-based and event-based tests with/without photons.
nuclearkevin
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adf4413
Revert "Remove unnecessary coord reset."
nuclearkevin
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ee01d16
Regold to account for coord fix.
nuclearkevin
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8f752cc
Fix periodic boundary conditions.
nuclearkevin
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4c2310e
Add tests for delta tracking boundary conditions.
nuclearkevin
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3f579d8
Only need the tolerance on the translational periodic BC.
nuclearkevin
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6fef6f7
Update tests to account for the removal of duplicate code & consolidation.
nuclearkevin
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8575c0b
Fix gold inputs.
nuclearkevin
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5749d3e
Final review.
nuclearkevin
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69028ae
Style changes.
nuclearkevin
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c29dd74
URR grid index fix.
nuclearkevin
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d14cd6d
More fixes for rare bugs that happen when finding a grid index.
nuclearkevin
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e3e65d4
Catch void majorants, clean up majorant killswitch.
nuclearkevin
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33156d3
Build majorant in parallel with OpenMP threads.
nuclearkevin
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dffe284
Style changes.
nuclearkevin
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e15495c
Consistent BC tolerance application.
nuclearkevin
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2da009c
Advancing in time.
nuclearkevin
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bc28103
Catch void materials.
nuclearkevin
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22c4c83
Apply more maxes to URRs.
nuclearkevin
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d4c4c20
Minor improvements, document statepoint changes.
nuclearkevin
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2a025aa
Apply suggestions from code review

nuclearkevin
and
pshriwise
committed
26f128d
Keep the linter happy.
nuclearkevin
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972e7d6
Documentation.
nuclearkevin
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7960638
Address non-majorant review.
nuclearkevin
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77f7cb6
Address majorant comments.
nuclearkevin
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5c21303
Formatting.
nuclearkevin
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51dbeee
Fix copy-paste error.
nuclearkevin
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6c01ceb
Fix the two-component estimator.
nuclearkevin
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53dd1bb
Regold MG survival biasing test for the 2-component fix.
nuclearkevin
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a08e80e
Style changes.
nuclearkevin
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881d031
Regold for fixed 2-component combined estimator.
nuclearkevin
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e0ea399
Now that it works, clean it up
nuclearkevin
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1f7c15b
Rename gold file directories.
nuclearkevin
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1d783ef
Add to settings.xml file description.
nuclearkevin
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f610907
Use openmc::vector.
nuclearkevin
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6c345f9
Address remaining review comments.
nuclearkevin
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3ac87b3
We do need this.
nuclearkevin
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aa79009
Add a check for surface filters.
nuclearkevin
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19bac5a
Catch bug in DAGMC/MOAB.
nuclearkevin
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231a084
Please the linter.
nuclearkevin
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2cd0d41
Update to account for inlining of electron/positron rxns.
nuclearkevin
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ff3259d
Regold delta tracking photon tests to account for inlining of electron/positron rxns.
nuclearkevin
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13d0297
Roll the version string forward to 0.15.5
nuclearkevin
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1d36d11

Commits on Aug 8, 2026

Roll the version string to 0.16.1.
nuclearkevin
committed
ca0a952
Squash hybrid tracking commits.
nuclearkevin
committed
d524b37
Squash hybrid tracking commits again.
nuclearkevin
committed
d214173