CPLEX Changelog#

20260414#

  • Changes in MP, see MP changelog.

20260310#

  • Added options mip:objdiff and mip:relobjdiff

20251210#

  • Option obj:multi:options: fix integer-valued objective-specific options.

20251121#

  • New option obj:multi:options to control whether multi-objective option suffixes are used.

  • Allow standalone mipdisplay=.., lpdisplay=.., bardisplay=.. without outlev.

20251015#

  • Changes in MP

  • Fixed multiobj=1/2 for a single objective. Running multiobjective for a single-objective model makes sense with a negative .objweight suffix.

20250924#

  • Option alg:start:advance

  • Added options to execute the CPLEX tuner (see tech:tunebase and other tech: options)

20250828#

  • Options tech:optionnativeread, tech:optionnativewrite to read/write CPLEX PRM files.

  • Options lim:(lower/upper)(cutoff/obj/objstop) for limiting search in the Simplex and Branch-and-Bound algorithms.

20250814#

  • Changes in MP

    • Improved preprocessing of logical and combinatorial expressions (options cvt:pre:unnest, cvt:pre:sort).

    • Option cvt:pre:boundlogarg (default 0) to bound arguments of logarithm nonnegative. Previously always done, sometimes deteriorating performance of nonlinear solvers.

  • Options alg:numericalemphasis, tech:memoryemphasis.

20250801#

  • Changes in MP

    • Tolerances set by options pre:feastol, pre:feastolrel both need to be violated to produce a warning on contradicting variable/constraint bounds. Previously the preprocessor failed on any violation, without letting the solver try.

    • Options cvt:compl, cvt:compl:eps control complementarity reformulations.

20250617#

  • Option lp:opttol (opttol).

  • Changes in MP

    • Multi-objective emulator: added support for objective-specific options via objective suffixes beginning with option_

    • Option cvt:unnest: bits 2 and 4 switch on inlining of linear and quadratic subexpressions produced during reformulations (by default on).

    • Options cvt:pre:ctx2ineq, cvt:pre:ctx2count to control context propagation into conditional comparisons #267.

20250429#

  • Fix a bug in parsing of quadratic expressions, which could wrongly parse products of unequal linear expressions, such as (x-3)*(x-z-5).

  • Options alg:dual and pre:dual are coordinated for compatibility with the legacy ASL driver.

20250424#

  • Changes in MP

    • Option cvt:qp2pass (default even faster parsing of quadratics)

  • Compatibility updates

    • Option netopt accepts numeric argument. For keyword-only, use option alg:network. Note the new default (compared to cplexasl): netopt=0.

    • Options netdisplay, netfeasibility, netfind, netoptimality, and netpricing

    • Options primal, dual (both dummy)

  • Fixed output logging incl. options mipdisplay, mipinterval, lpdisplay, bardisplay, modisplay, netdisplay

20250329#

  • Changes in MP:

    • Option cvt:multoutcard to limit the size of out-multiplied QP expressions. Can improve speed on large models.

    • Improved parsing of quadratic expressions.

20250308#

  • Changes in MP.

20241212#

  • Releasing with CPLEX version 22.1.2

20241206#

  • Added support for sensitivity analysis (keyword sensitivity)

  • Added keywords mip:nodefile, tech:workdir, tech:workfilelim

20240828#

  • Options primalopt, dualopt, baropt, siftopt, netopt, bendersopt are now flags (e.g. they have to be set without a value)

20240823#

  • CPLEX MP driver is now the default. To use the previous ASL-based driver set: option solver cplexasl;

  • Added many options available in the ASL driver

  • Notable changes with ASL driver:

    • Keyword ‘basis_cond’ is now ‘kappa’ and follows the standard MP implementation

    • Multiobjective optimization follows the MP standard implementation

    • Choosing solution algorithm for the LP problems or the initial MIP subproblem (formerly mipstartalg) now follows the same standard as other MP drivers: see alg:method in the -= output

    • Former option timing is now implemented through the corresponding MP feature. To print the number of available cores use tech:numcores.

    • Use MP feature tech:writemodelonly instead of writeprob + nosolve. Note that nosolve still applies when specifying writemipstart

  • Conversion of basis status for constraints depending on sense

20240801#

  • Fix a problem that occured when reporting IIS

  • Removed some noise from console output

20240724#

  • Option acc:_all

    • Useful to disable all reformulations (acc:_all=2), or force linearization (acc:_all=0).

  • Option cvt:prod

    • Controls reformulation of binary products into logical constraints.

  • Faster input of quadratic expressions.

20240617#

  • Multi-objective emulator

    • obj:multi=2 forces emulation, even if MO natively supported.

    • Fixed a bug in the objective degradation suffixes .objasbtol, .objreltol.

20240604#

  • Presolve division by constant, resulting in fewer constraints

  • Fix no-solution case in multi-objective emulator

20240529#

  • Multi-objective emulator

    • All flat MP solvers support multi-objective mode (obj:multi=1), either natively, or via emulation.

    • Suffixes .objpriority, .objweight, .objabstol, .objreltol.

    • [BREAKING] Default intuitive handling of .objweight, see option obj:multi:weight, even when natively supported.

20240429#

  • [BREAKING] Merged report_times and timing; they are now aliases, set the value to 1 to have basic info, to 2 to have more detailed info.

20240320#

  • SOS constraints.

    • Fixed handling of SOS2 constraints created by AMPL as reformulations of PL expressions (option pl_linearize 1, default; set to 0 to use the solver’s native PL functions or MP linearization.)

    • Disallow repeated weights for SOS constraints (suffixes .sosno/.ref.)

  • Option report_times

  • Unused acc: options.

    • The constraint acceptance options acc:... for non-handled constraints are ignored (previously triggered error.)

20240115#

  • Solve result codes.

    • List codes by running (solver) -!

    • [BREAKING] Standardized codes. Major changes:

      • 100-199 (solved?) means solution candidate provided, but can be suboptimal/infeasible

      • 300-349 means unbounded problem but feasible solution returned

      • 400-449 means limit/interrupt but feasible

    • [BREAKING] sol:chk:fail returns code 150 (solved?)

  • Improved translation of SOCP constraints.

    • Options cvt:socp, cvt:socp2qc.

  • Compact solution check warnings

  • Fixed presolve of the power function #226.

  • Added fixed model for mip:basis

  • Added options:

    • alg:method and flags to choose the solution algorithm

    • mip:nodemethod to choose the algorithm used for MIP node problems

    • lp:solutiontype to choose if to use crossover to get a basis basis solution after barrier

20231122#

  • Public beta; implemented most features in MP: model export, warm start, input and output basis, feasibility relaxation, multiple solutions, kappa, unbounded rays, IIS, return MIP gap, return dual bound

  • Native Model support:

    • continuous and integer variables

    • multiple objectives, quadratic objectives

    • linear and quadratic constraints, indicator constraints and PL functions

    • special ordered sets (type 1 and 2)

20231117#

  • MP update: fixed graceful exit on Ctrl-C from AMPL in Linux and fixed issue with reading text-format NL files

20230815#

  • Fixed a bug causing repeated names for auxiliary variables and constraints.

  • Option values can be assigned without ‘=’.

  • Changed default tolerance for strict comparisons to 0 (option cmp:eps, #102.)

  • Fixed a bug where equivalent conditional comparisons were not unified.