NVIDIA cuOpt Files

Release Notes 26.02

New Features (26.02)

• New parallel reliability branching inside MIP solver
• Mixed Integer Gomory, Mixed Integer Rounding, Knapsack and Strong Chvatal Gomory cuts are now added at root node
• Added an option to use batch PDLP when running strong branching at the root. Based on Batched First-Order Methods for Parallel LP Solving in MIP (Nicolas Blin, Stefano Gualandi, Christopher Maes, Andrea Lodi, Bartolomeo Stellato)
• Quadratic programming (QP) solver is now generally available (previously beta)
• New infeasibility detection option for PDLP's default solver mode Stable3
• Solutions callbacks added to C API. Users can now retrieve the dual bound and pass in user data
• Multiple new diving techniques added for finding integer feasible solutions
• The PSLP presolver is enabled by default for LP problems. Use the presolve option to select Papilo or disable
• Added a batch solve for routing to boost throughput for many similar instances
• Added experimental support for determinism in the parallel branch-and-bound solver. GPU heuristics are not supported yet in this mode

Breaking Changes (26.02)

• The signatures of the solution callbacks have changed for the Python API
• To use PDLP warm start, presolve must now be explicitly disabled by setting CUOPT_PRESOLVE=0. Previously, presolve was disabled automatically

Improvements (26.02)

• Improved primal/dual warm start for PDLP's default solver mode Stable3
• Quadratic objectives can now be constructed via a matrix in Python API
• QP barrier now updates and solves augmented system on the GPU
• Improved performance for LP folding
• Probing implications and better variable ordering to strengthen presolve and branching
• Replace deprecated cuDF Column/Buffer APIs with pylibcudf and public cuDF interfaces
• Modernize dependency pinnings; make CUDA runtime linkage static for portability
• Build/tooling: add --split-compile, --jobserver, Clang host build, ThreadSanitizer, improved container scripts, and branch/commit metadata in images
• Use explicit cudaStream_t with cub::DeviceTransform and non-blocking streams for GPU control
• Enable barrier LP tests, add regression testing, and add SonarQube static analysis
• Added parameter for specifying the random seed used by the solver

Bug Fixes (26.02)

• Fixed an issue with incorrect signs of dual variables and reduced costs on maximization problems
• Fix out-of-bounds in dense-column detection in barrier
• Correct infeasible-list handling to avoid incorrect infeasibility reports in dual simplex
• Fix race conditions found via Clang host build + ThreadSanitizer
• Resolve CUDA–Numba version mismatches with cuDF
• Fix device code to include required trailing return types
• Fix issue in crossover after dualization in barrier
• Repair container build and test failures
• Miscellaneous additional fixes and stability improvements

Documentation (26.02)

• Update README and top-level docs for current build and usage
• Document new repository branching strategies and release-cycle details in README and CONTRIBUTING
• Add best practices for batch solving