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Exploit degeneracy in MIP - #1685

Merged

rapids-bot[bot] merged 154 commits into

NVIDIA:mainfrom

chris-maes:dual_degenerate

Oct 10, 2026

Merged

Exploit degeneracy in MIP#1685
rapids-bot[bot] merged 154 commits into
NVIDIA:mainfrom
chris-maes:dual_degenerate

Commits on Jul 20, 2026
- Fix bugs causing primal simplex to cycle. Enable primal simplex cleanup after dual simplex
  chris-maes
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  63d1ba4
Commits on Jul 21, 2026
- Primal simplex pivots on dual degenerate problems to reduce integer infeasibility
  chris-maes
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  8b1e60b
- First stab at using the feasibility pump on a reduced problem on the optimal face
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  17b2725
Commits on Jul 24, 2026
- Add check for fast pivot using slacks
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  ff6f460
- Merge remote-tracking branch 'origin/main' into dual_degenerate
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Commits on Jul 27, 2026
- Enable primal simplex. Solves 85/93 NETLIB LPs in under 1 minute
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  900805a
Commits on Jul 28, 2026
- Use primal simplex to remove a perturbation from dual simplex
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  efc9fb0
Commits on Jul 29, 2026
- Clean up logging of degenerate feasibility pump
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  cf3d4d4
- Add work estimates to primal simplex
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  a7cfd19
- Display work estimate and simplex iterations
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  6dfebbf
Commits on Aug 4, 2026
- Primal in crossover. Crossover tolerance mismatch fix. Pipe work estimates for root relaxation. Add initial perturbation parameter
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  99d7ead
Commits on Aug 6, 2026
- Merge remote-tracking branch 'cuopt-nvidia/main' into dual_degenerate
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  adcb8c2
- Address coderabbit review comments
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  0cfc746
- Address coderabbit review comments
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  committed
  1c2c01a
- Use tight tol for reduced costs zero check
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  b2de00d
- Try to clean up normalization
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  a92825c
- Remove AI slop
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  31436ba
- Style fixes
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  ef75207
- Fix work estimate bug in BFRT. And improve work estimates
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  117b2b4
Commits on Aug 7, 2026
- Harris ratio test; timers in primal; limit feasibility pump to do less work than root relaxation
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  99207b2
Commits on Aug 8, 2026
- Add reduced cost bounds table. Change objective in feasibility pump. Fix work limit in feasibility pump. Check for reduced cost violation before calling primal simplex. Check if we reduced number o…
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  eb47c20
Commits on Aug 12, 2026
- V3 of pump and pivots, better work estimates, also exploit primal degeneracy
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  7641ad3
Commits on Aug 14, 2026
- Devex pricing in primal; try to remove perturbations in dual
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  39cb576
Commits on Aug 26, 2026
- 15% improvement in dual simplex; new BFRT, perturbations, initial point, etc.
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  f54d57f
- Avoid double counting slope contribution from variable selected in single_pass
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  917ccaf
Commits on Aug 27, 2026
- Have BFRT decide on bound flips
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  36ca4d3
Commits on Aug 28, 2026
- Improve BFRT work estimates
  chris-maes
  committed
  75a1e97
- Merge remote-tracking branch 'cuopt-nvidia/main' into dual_degenerate
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  committed
  47e0848
Commits on Aug 29, 2026
- Fix bug in not handling concurrent halt. Use zero_tol in step-length computation to try to remain dual feasible
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  committed
  d983159
Commits on Sep 2, 2026
Commits on Sep 3, 2026
- Style fixes
  chris-maes
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  bfcbb15
- Prefer large pivots with Harris ratio buckets
  chris-maes
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  c3a0251
- Add parameters to control degenerate pivots
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  ef5ff66
- Style fixes
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  2e02e23
Commits on Sep 4, 2026
- Snapshot slack columns for branch-and-bound workers
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  0f95053
Commits on Sep 9, 2026
- Restrict concurrent halt to root LP solves
  chris-maes
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  9acaebc
- Preserve caller cancellation in node LP solves
  chris-maes
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  4da4349
- Prefer large pivots with Harris ratio buckets
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  8c93985
Commits on Sep 10, 2026
- Remove tiny perturbations before retrying dual simplex
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  553b1fc
- Replaced cusparse wrappers with simple unique_ptrs and more RAII (#1342)
  
  Bubullzz
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  62638a7
- Forward routing gRPC settings and map node name strings to ints (#1837)
  
  tmckayus
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  74865d3
- Set Papilo back to the main branch (#1694)
  
  nguidotti
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  b43fae0
- Adopt CUDA stream compatibility accessors (#1858)
  
  bdice
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  a0435e5
- move server LPData transform into a standalone function (#1848)
  
  tmckayus
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  0f79f11
- refactor: make to_optimization_problem a free function (#1802)
  
  authored and
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  34ac7fc
- Extract LP create_data_model/create_solver into conversion.py (#1849)
  
  tmckayus
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  7e50453
- Bump cuopt-java compile target from Java 11 to Java 17 (#1865)
  
  ramakrishnap-nv
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  committed
  447aa22
- extract routing server data creation routines into standalone module (#1850)
  
  tmckayus
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  49f6d48
- move server data compression handling into a standalone module (#1851)
  
  tmckayus
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  chris-maes
  committed
  e1238c3
- fix(build): pin RAPIDS_BRANCH and shared-workflows to release/26.10 (#1870)
  
  ramakrishnap-nv
  authored and
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  70b0955
- change Python grpc client so wait loop happens in Python (#1857)
  
  tmckayus
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  committed
  4def469
- add a smoke test to ensure server images start correctly (#1646)
  
  tmckayus
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  committed
  8e3f264
- refactor: keep the GPU warm-start path out of host-only translation units (#1803)
  
  ramakrishnap-nv
  authored and
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  52d6f08
- extract result file support logic to be shared by proxy (#1869)
  
  tmckayus
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  committed
  0a4415b
- update variable type (#1783)
  
  Iroy30
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  e6196f5
- Move deprecated server modules into utils/deprecated. (#1874)
  
  tmckayus
  authored and
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  committed
  cc21c5c
- build: add the CUDA-free cuopt_client library (#1804)
  
  ramakrishnap-nv
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  51f134d
Commits on Sep 11, 2026
- Remove BFRT debug code
  chris-maes
  committed
  deade2c
- Remove tiny perturbations before retrying dual simplex
  chris-maes
  committed
  60efd8b
- Remove BFRT debug code
  chris-maes
  committed
  4d9309c
- Remove more debugging code
  chris-maes
  committed
  f6f82f4
- Remove unused unscaled max obj coeff
  chris-maes
  committed
  3e04179
- Remove unused unscaled max obj coeff
  chris-maes
  committed
  2d948ec
- Remove more debugging code
  chris-maes
  committed
  ae8f903
- Check time and concurrent halt in BFRT
  chris-maes
  committed
  6deb6bb
- Improve handling of primal simplex return status
  chris-maes
  committed
  3311cdb
- Remove primal clean up. We now do this inside dual simplex
  chris-maes
  committed
  2920576
- Check time and concurrent halt in BFRT
  chris-maes
  committed
  52d8ccb
- Improve handling of primal simplex return status
  chris-maes
  committed
  ffaec11
- Remove primal clean up. We now do this inside dual simplex
  chris-maes
  committed
  2ede6e1
- Fix comment
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  committed
  74146b9
- Fix comment
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  committed
  53be7d4
- Fix messages
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  committed
  88e37c5
- Fix messages
  chris-maes
  committed
  8e0d79c
- Remove unused variable
  chris-maes
  committed
  7e9545a
- Fix method. Add limit check at top of loop to avoid infinite loop
  chris-maes
  committed
  b6a9318
- Fix method. Add limit check at top of loop to avoid infinite loop
  chris-maes
  committed
  61ddbf1
- Refactor primal cleanup
  chris-maes
  committed
  fa84590
- Refactor primal cleanup
  chris-maes
  committed
  f084344
- Fix work estimate initialization
  chris-maes
  committed
  cfcc5a4
- Fix work estimate initialization
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  committed
  dba71c3
Commits on Sep 12, 2026
- Remove unused variable
  chris-maes
  committed
  952cf05
- Merge simplex improvements into dual_degenerate
  chris-maes
  committed
  3883aa1
- Merge cuopt-nvidia/main into simplex improvements
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  committed
  f8237e6
- Merge updated simplex base into dual_degenerate
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  committed
  f020595
- Format simplex improvements
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  committed
  a7659d7
- Merge shared formatting into dual_degenerate
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  committed
  babeff2
- Format MIP extensions
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  committed
  c56bdae
- Rename simplex parameters and default primal pricing to Devex
  chris-maes
  committed
  8523f2b
- Rename simplex parameters and default primal pricing to Devex
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  9d10430
- Merge shared simplex parameter updates
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  a9003b0
- Stop recursive sub-MIPs when branch-and-bound terminates
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  committed
  bc99b1e
- Use sparse reduced-cost updates for MIP strengthening
  chris-maes
  committed
  8dd900b
- Fix primal simplex pricing parameter test
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  30cfc15
- Merge branch 'primal_and_dual_simplex_improvements' into dual_degenerate
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Commits on Sep 14, 2026
- Validate dual simplex cutoffs with the original dual objective
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  c642962
Commits on Sep 15, 2026
Commits on Sep 16, 2026
- Avoid redundant reduced-cost product in cutoff validation
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  committed
  9206716
Commits on Sep 18, 2026
Commits on Sep 19, 2026
Commits on Sep 21, 2026
Commits on Sep 22, 2026
Commits on Sep 23, 2026
Commits on Sep 24, 2026
- Merge remote-tracking branch 'cuopt-nvidia/main' into dual_degenerate
  chris-maes
  committed
  26b649f
Commits on Sep 28, 2026
- Refactor to address review comments
  chris-maes
  committed
  a59a053
- Fix test failures
  chris-maes
  committed
  bafd54e
- Merge remote-tracking branch 'cuopt-nvidia/main' into dual_degenerate
  chris-maes
  committed
  7ca3bb8
Commits on Sep 29, 2026
- Apply eligible reduced-cost bounds and restore general-integer tightening
  chris-maes
  committed
  1718c29
Commits on Sep 30, 2026
- Skip dense reduced-cost strengthening directions and track work
  chris-maes
  committed
  81ff49a
Commits on Oct 1, 2026
- Limit cumulative root integer pivot work
  chris-maes
  committed
  3295c97
Commits on Oct 5, 2026
- Restrict default integer pivots to root and heuristic workers
  chris-maes
  committed
  c6d702b
Commits on Oct 6, 2026
- Simplify reduced-cost strengthening diagnostics
  chris-maes
  committed
  c5e6230
Commits on Oct 7, 2026
- Merge remote-tracking branch 'cuopt-nvidia/main' into dual_degenerate
  chris-maes
  committed
  27a03d1
Commits on Oct 9, 2026

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