HISTORY

# PuLP, Copyright J.S. Roy (js@jeannot.org), 2002-2005
#       Copyright S.A.Mitchell (s.mitchell@auckland.ac.nz), 2007-
#       Copyright F.Peschiera (pchtsp@gmail.com), 2019-
# See the LICENSE file for copyright information.
4.0.0a11 2026-06-19
    HiGHS API accepts warmstarts
4.0.0a10 2026-06-01
    CPSAT has msg=True
    silenced XPRESS warning at startup
4.0.0a9 2026-05-27
    new solver: CPSAT
    refactor unit tests
4.0.0a8 2026-05-22
    much faster MPS write in the Rust path (large models, order-of-magnitude speedup)
    HiGHS API: ``kSolutionLimit`` and ``kMemoryLimit`` statuses; best MIP solution returned
        when status is not optimal
    ``LpStatusUndefined`` for infeasible or unbounded problems
    cuOpt handles UnboundedOrInfeasible status; variable category mapping via Rust helper
    ``XPRESS_PY`` updated for Xpress 9.8 with backward compatibility
    MPS round-trip tests and fixtures; CI and solver documentation updates
4.0.0a6 2026-04-29
    Rust core uses ``Arc``/``Mutex`` instead of ``Rc``/``Weak`` so Python debuggers do not
        crash the extension
4.0.0a5 2026-04-15
    solvers receive only variables used in the model; SOS constraints moved to ModelCore in
        Rust
4.0.0a4 2026-04-14
    removed bundled CBC binaries and the ``PULP_CBC_CMD`` solver; CBC is used via
        ``COIN_CMD`` with optional ``pip install pulp[cbc]`` (cbcbox) or a ``cbc``
        executable on PATH
4.0.0a3 2026-04-13
    modelling API split into ``pulp/core/``; faster ``lpSum`` for variables
    type stubs for ``_rustcore``; solvers use direct Rust model access without Python-side
        handles
4.0.0a1 2026-04-05
    first alpha of the 4.x line; Rust-backed core (PyO3 0.28) is now used for
        much of MPS and LP import/export and related model logic
    LpVariable and modelling API adjustments (variables without requiring a
        model up front); examples, tests, and solver glue updated accordingly
    simplified structure returned from MPS reading; clearer errors from the
        native layer
    typing and internal cleanups; direct access paths for Rust-backed model data
    work around highspy / Rust extension interaction (RTLD_GLOBAL preload) and
        HiGHS_CMD fixes; GLPK API fixes alongside the Rust paths
    CI uses maturin-action for multi-platform wheels and PyPI publishing
    compatible with Python 3.10 and up
3.3.2 2026-05-25
    ``PULP_CBC_CMD`` deprecated (removed in PuLP 4.0); use ``pip install pulp[cbc]`` and ``COIN_CMD`` instead
    default solver prefers ``COIN_CMD`` when CBC is available on ``PATH``
    ``set_v4_migration_warnings(False)`` silences migration warnings
    compatible with Python 3.10 and up
3.3.1 2026-04-30
    PuLP 4.0 migration helpers: ``LpProblem.add_variable*``, ``constraints()`` as list, ``get_constraint_by_name``
    deprecations for legacy ``LpVariable`` construction, dict-like ``prob.constraints``, ``addVariable`` / ``addVariables``, ``LpConstraintVar``
3.3.0 2025-09-18
    fixed some docs
    changes to unit tests
    mypy fixes
    fixes to GUROBI API
    callbacks in CPLEX_PY API
    fixes to CUOPT API
    compatibility with new XPRESS_PY API
    allow joint installation of python-based APIs
    initial experimental Rust core (crate pulp-rust-core) and optional
        pulp._rustcore extension exposed via LpProblem.toRustModel
3.2.0 2025-05-29
    Callbacks in HiGHS solver
    Added CuOpt solver
3.1.0 2025-03-24
    cleaned old configuration files and functions
    moved to pyproject.toml instead of setup.py
    migrate to uv packaging
    support python >= 3.9
    add incomplete CyLP solver API
3.0.0 2025-02-19
    Improved performance for large models
    new solvers: SAS SAS94 and SASCAS
    improvements to HiGHS API
    some typing added
    Add support for bound type `MI` in MPS reading
    minor fixes
2.9.0 2024-07-12
    HiGHS available as solver
    added HiGHS_CMD to github actions
    deactivated warnings on msg=False
    minor fixes
2.8.0 2024-01-12
    mip start in HiGHS_CMD and SCIP_PY
    GUROBI solver with environment handling
    added COPT solver
    added gurobi, highs, xpress, copt to github actions
    cbc arm binary
    fixes to SCIPS
    took out deprecations in arguments
2.7.0
    added HiGHS solver
    added XPRESS_PY solver
    fixed bugs
    updated docs
2.6.0 2021-12-04
    dropped packaged choco
    fixed bugs
    deprecated 'indexs' parameter LpVariable dicts and matrix
2.5.1 2021-09-28
    updated docs
    fixed minor issues
    cbc now uses wall-time for timeLimit
2.5.0 2021-08-11
    measuring wall time and cpu time
    unittests of timeLimit
    black formatting
    refactored tests per solver
    dropped support for CPLEX_DLL
2.4 2020-12-22
    added mps reading support
    updated docs
    fix bug with no objective in prob.toDict()
2.3.1 2020-10-22
    change naming of solver utility functions to camelcase
    fixed gurobi license detection
    fixed scip options and added timeLimit argument
    changed docs
2.3 2020-08-04
    Added plugin page in docs
    Standardize arguments of solvers to appear in docs
    Fixes to import and export of LpProblem and solver
    Added warm start to GUROBI
2.2 2020-04-06
    Contribution files
    Standard arguments: logPath, gapRel, gapAbs
    Import and export solver objects
    Import and export LpProblem
    Took out amply to its own package
    Standard tmp file handling in _CMD solvers
    Refactored writeMPS    
2.1 2020-04-06
    Added MOSEK solver
    New documentation
    Put tests inside package
    Added warm start to CPLEX_PY
2.0 2019-11-23
    Restructured solvers code
    Added unittests package
    Added CHOCO solver
    Added warm start for CBC_CMD, GUROBI_CMD, CPLEX_CMD
    Automated deploy
1.6.1, 2015-12-25
    Fix for dummy variables
1.5.4, 2013-03-18
    Added cbc support for osx (hopefully)
1.4.9, 2011-03-30
    Added support for cplex runtime licenses
    Made PULP_CBC_CMD the default LP solver for linux
    Included 32 and 64 bit versions of cbc
1.4.8, 2011-03-30
    Overdue fix for zero coeff issue
    bugfix for default cat for LpVariable.dicts
    moved tests to a different file
1.4.6, 2010-01-25
    Bugfix
1.4.4, 2010-01-24
    CBC 2.4 cmd line solver added
    CoinMP dll 1.4.0 uses trunk version
    CoinMP library object now accessed through COINMP_DLL.lib
    Config files now include a %(here)s syntax to identify paths
    Included solvers now moved to solvers directory
1.4.2, 2009-12-31
    Fixes before coin Announcement
1.4.0, 2009-10-16
    Added Elastic Constraints
    Added Fractional Constraints (tests yet to be added)
    Added limited resolve for gurobi
    Changed version numbers for coin import
    Fixed COIN_CMD
    Changed code to be compatible with python 2.4
1.3.08, 2009-08-08
    Bugfix COINMP_DLL
1.3.07, 2009/06/26
    Changes for pypi
1.3.01, 2009/06/25
    Made constraints ordered dictionaries
    Small changes to parameters of COIN_DLL solver
    Removed string exceptions
    added the constraints from other LpProblems to LpProblem.extend()
1.3.00, 2009/06/21
    Added GUROBI Solver
1.23, 2009/05/25
    Removed old style MEM solvers
    Cleaned up CPLEX_DLL interface
    Added Sequential solve function
1.22, 2009/04/03
    Added Cplex IntegerOptimalTolerence setMemoryEmphsis, and clarified linux
    installation instructions
1.21.02, 2008/07/29
    Added epagap, and logfile in CPLEX_DLL
1.21, 2008/07/28
    Added Combination and Permutation functions
    Bugfix for configsolvers
    Updated setup.py to start to compile everything
1.20, 2008/06/08
    Certified for inclusion in Coin-Or
    Spilt the solver and constant definitions into separate files
    Unit Tests make more explicit
    Included external definitions for CoinMP.dll
    No Makefile
1.11, 2008/03/01
    Contributed by Stuart Mitchell s.mitchell@auckland.ac.nz.
    Contains dll solvers that are accessed with the ctypes library.
    Can use the CoinMP.dll solver from the coin-or project.
    Added column-wise modelling and resolve capabilities.
    Wiki added with plenty of examples  aphi038@ec.auckland.ac.nz
1.9, 2007/08/06:
    Stuart Mitchell
    Added support for cplex 10.1.0 using ctypes library
    Added support for the CoinMP.dll using ctypes library
    Added distutils setup
    Added a configuaration file pulp.cfg
1.1, 2005/05/03:
    Fix an strange interpretation of unbounded integer variables by COIN and CPLEX
    LP return codes are simplified.
    C interface modules for GLPK, COIN and CPLEX
    Windows compatibility
1.0, 2004/02/29: First release