XPRESS Changelog

20231117

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

20231103

  • Improved translation of logical constraints: inlining of nested disjunctions and conjunctions; fewer auxiliary binary variables.

20231017

  • Fixed a bug in NL reader on Windows.

20230919

  • mp_options. Receive mp_options from AMPL (for all MP solvers). They are parsed before (solvername)_options.

  • Solution checking: relative tolerance sol:chk:feastolrel; options sol:chk:round, sol:chk:prec.

20230831

  • Solution checking, options sol:chk:* (experimental).

  • Preprocess And/Or constraints.

20230817

  • Alternative solutions: solve status equal to that of the final solution.

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

  • Option values can be assigned without ‘=’.

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

20230808

  • Updates for Xpress 9.2 (42.01.01), which include many performance improvements in the MIP solver.

  • Non-convex quadratic problems are now solved to global optimality by default.

  • Added options ‘mip:heurshiftprop’, ‘tech:backgroundthreads’ and ‘tech:backgroundselect’.

  • The range of the control ‘mip:feasibilityjump’ was extended.

20230728

  • Option ‘tech:writesolution’.

20230727

  • Fixed a memory leak #217

  • Fixed quadratic constraints

20230726

  • MP: fixed inequalities of integer expressions with non-integer constants, see test_int_non_int.mod.

20230724

  • Option [solver_]auxfiles rc; transfers names of variables and linear constraints into the model; (solver)_options ‘cvt:names=0-3’ controls names.

20230714

  • Options barrier/primal/dual/network like in ASL.

20230621

  • Fix quadratic objective with repeated subexpressions.

  • Fix reformulation of ==> / else.

20230616

  • Changes in MP.

  • Eliminated spurious warnings

  • Fixed passing of quadratic objective

20230607

  • Amended detection and display of licensing errors

  • Licensing allows now usage of an XPRESS license from an AMPL-based deployment

20230603

  • Added option ‘tech:logfile’ to enable output to a log file

20230424

  • Changes in the MP library: added variable names support and removed spurious starting solution

20230227

  • Eliminated warning message when a non feasible solution is added as a starting point for the MIP search

20230207

  • Changes in the MP library

20221228

  • Changes in MP

20221222

  • Bug fixes in MP

20221211

  • Changes in MP: added the ==> else operator Implemented implication with ‘else’: constr1 ==> constr2 [else constr3]

  • Changes in MP: PLApproxRelTol, PLApproxDomain Parameters to control piecewise-linear approximation. cvt:plapprox:reltol default value changed from 1e-5 to 0.01.

20221208

  • First release of the MP-based driver for Xpress (solver version 9.0)

previous

XPRESSASL Options

next

XPRESSASL Changelog