Fixed Issues in Gurobi Optimizer 12.0#

This page lists the issues fixed in Gurobi 12.0.0.

Fixed Issues in Gurobi 12.0.0#

Optimizer#

  • Properly sign Windows dll and executables and .NET library

  • Fixed issue with empty error messages for function calls from callback

  • Fixed issue with infinite recursion if GRBmsg is called from within a message callback

  • Reduced number of malloc calls to avoid issues with memory fragmentation that may lead to out-of-memory errors

  • Removed runtime overhead from querying OS information for logging that could be noticed when solving thousands of tiny models

  • Fixed a potential segmentation fault when setting an integer attribute of a general constraint

  • Fixed read error for OPB files at the end of the file

  • Fixed issue in OPB file reader when the resulting quadratic problem has more than 2 billion quadratic terms

  • Fixed very rare numerical issue in presolve that could lead to wrong answers

  • Fixed numerical issues in presolve that could lead to a wrong declaration of infeasibility

  • Fixed numerical issues in parallel column presolve reduction that could lead to wrong answers

  • Fixed issue with inconsistent objective values if uncrushing improves (for numerical reasons) the objective value

  • Fixed rare issue with presolve reduction that combines an inequality with an equation that is parallel to it, leading to a wrong answer

  • Fixed issue in presolve with general piecewise-linear constraint that can lead to large constraint violations

  • Fixed potential segmentation fault in presolve for models with both quadratic equalities and a quadratic objective

  • Fixed rare issues in MIQCP presolve that could lead to wrong answers

  • Fixed some numerical issues in the simplex algorithm

  • Fixed numerical issue in dependent row presolve for LPs that could lead to wrong declaration of infeasibility

  • Fixed issue with infinite cycling in QP simplex

  • Fixed very rare issue with super basic variables handling in LP relaxations of MIPs that could lead to wrong answers

  • Fixed memory leak in simplex when switching from primal to dual and solving again with primal

  • Fixed issue with dual violations if a continuous model with a piecewise-linear objective is solved by barrier without crossover

  • Fixed bugs in barrier that could arise for models with more than 2 billion non-zeros

  • Fixed potential segmentation fault in SOCP when there are more cones than linear constraints in the model

  • Fixed issue with wrong objective sense for maximization models that are solved with barrier, use the explicit dual model and exploit symmetry

  • Fixed issue with IntegralityFocus=1 that could lead to a wrong answer

  • Fixed issue in MIP cleanup with accepting a solution that has too large constraint violations

  • Fixed numerical issue in cut lifting that could lead to wrong answers

  • Fixed very rare segmentation fault in a special case of clique and implied bound cuts

  • Fixed performance issue with the interior point heuristic for nonconvex MIQCPs not benefitting from the user-specified PStart values because they are incorrectly discarded

  • Fixed issue with an infinite loop in MIQCP solving if outer approximation is unbounded

  • Fixed numerical issue with small values in presolve for quadratic constraints that could lead to wrong answers

  • Fixed bug with spatial branching for nonconvex models that could result in excessively large node files or memory consumption

  • Raise error earlier if there are more than 2 billion quadratic terms in the quadratic constraints

  • Removed wrong warning log message about piecewise-linear objective for an IIS solve on a model with general function constraints

  • Fixed issue with incorrect handling of the WorkLimit parameter in individual multi-objective environments

  • Fixed issues with getting a wrong primary objective function in a multi-objective model without an update call before setting the secondary objective

  • Fixed inconsistencies in the interplay of the global Threads parameter and the Threads parameters of concurrent environments

Tuning Tool#

  • Fixed handling of fixed parameter settings in remote tuning sessions

gurobipy#

  • Fixed usage of np.array() for numpy 2.0 compatibility

Compute Server, Cluster Manager, and Instant Cloud#

The list of fixed issues for Compute Server, Cluster Manager, and Instant Cloud can be found here.