Fixed issues in Gurobi Optimizer 11.0#

This page lists the issues fixed in each technical release in the 11.0.x series.

Fixed issues in Gurobi 11.0.3#

  • Fixed numerical issue with an underflow in lifting during presolve

  • Fixed issue in tuning tool with objective scaling

  • Fixed bug with querying constraint names from Compute Server if names are really long

  • Fixed numeric error during conversion of QCPs into standard form

  • Fixed numerical issue in singular basis handling of simplex for free variables

  • Fixed uninitialized memory read in heuristics when crushing solutions through presolve

  • Fixed numerical issue in simplex when applying very small perturbations

  • Fixed logging issue with missing header line if simplex solve is resumed

Fixed issues in Gurobi 11.0.2#

  • Fixed incorrect result after using GRBconverttofixed

  • Fixed segmentation fault in barrier ordering for huge models

  • Fixed numerical issue with logistic function constraints that lead to wrong infeasibility claim

  • Fixed segmentation fault when linearization of Q objective leads to more than 2 billion terms

  • Fixed segmentation fault on Windows with Compute Server and piecewise linear objectives during model creation

  • Fixed a numerical issue in QP simplex

  • Fixed bug with using a wrong solution as forced MIP start for multi-objective models that leads to invalid solutions

  • Fixed bug with ModelSense attribute returning garbage after using concurrent LP with SolutionTarget=1

  • Fixed segmentation fault with using concurrent environments on Windows

  • Fixed wrong solution issue when crossover is skipped for barrier inside concurrent LP with SolutionTarget=1

  • Fixed a numerical issue in cover cut lifting that can lead to cutting off an optimal solution

  • Fixed segmentation fault with the combination of SolutionTarget=1 and PreDual=1

  • Fixed integer overflow in barrier nested dissection ordering that can lead to a segmentation fault

  • Fixed bug with reporting a wrong best bound in NoRel heuristic log for maximization problems

  • Fixed potential data race condition when multiple Gurobi environments are created from parallel threads

  • Fixed issue in gurobipy that setting string-valued attributes fails on 0-dimensional MVar objects

  • Fixed potential wrong answer bug in presolve with non-linear constraints and biconnected components

  • Fixed performance bug with symmetry computation on models with dense quadratic objectives

  • Fixed bug with overshooting the time limit in MIP IIS

  • Fixed bug with getting a big violation after symmetry unfolding or uncrushing simplex solution for SolutionTarget=1

  • Improved numerics in IIS calculation to reduce chances for producing an IIS that is not irreducible

  • Fixed segmentation fault for super long variable names in MPS reader

  • Fixed potential segmentation fault in strong branching when LP relaxation was dualized

  • Fixed sporadic declaration of optimality of massively sub optimal solution on models with lazy constraints

  • Fixed potential nondeterminism in spatial branching for non-convex MINLPs or MIQCPs

  • Fixed numerical issue in Euclidean algorithm based presolve reduction

  • Fixed bug with sending corrupted data to Cluster Manager on arm64 chips in batch mode

Fixed issues in Gurobi 11.0.1#

  • Improved numerics in presolve propagation on variables that appear nonlinear terms

  • Fixed segmentation fault in LP presolve aggregator

  • Fixed rare wrong answer bug with using a wrong cutoff value in presolve

  • Fixed numerical issue in in parallel rows reduction that can lead to wrong infeasibility claims

  • Fixed bug in dual presolve with fixing unbounded variables to an infinite value

  • Fixed numerics in domain propagation of node presolve to avoid wrong answers

  • Fixed numerical issue in presolve with fixing variables when using NumericFocus=2 or 3

  • Fixed bug with the objective constant being missing in the presolved model obtained my model.presolve()

  • Fixed segmentation fault in presolve probing

  • Fixed sign issue with calculating unbounded rays for free variables

  • Fixed rare bug in simplex with free variables dropping from basis

  • Fixed bug in work tracking that can lead to excessive spin time in concurrent simplex

  • Fixed performance issue when lazy constraints are involved

  • Fixed bug with bogus declaration of infeasibility

  • Fixed numerical issue with scaling if lazy constraints are involved

  • Fixed bug with NodeLimit=0 not being respected correctly

  • Fixed very rare bug with potentially getting non-deterministic behavior in parallel MIP solves

  • Fixed numerical issue in a heuristic that can lead to solutions with big violations

  • Fixed uninitialized memory read caused by compiler bug on ARM linux64

  • Fixed segmentation fault when copying a model with recording into a new environment that has no recording

  • Fixed segmentation fault with very long file names used for reading or writing model files

  • Fixed bug with reading solution attribute files for Compute Server

  • Fixed rare bug in presolve for quadratic constraints

  • Fixed very rare sign issue in quadratic constraint to SOC conversion

  • Fixed incorrect bound flip in QP simplex that could lead to wrong answers

  • Fixed uninitialized memory access in MIQCP presolve

  • Fixed bogus declaration of infeasibility or unboundedness in MISOCP presolve

  • Fixed segmentation fault when re-solving QPs using warm starts

  • Fixed error message regarding wrong sorting of breakpoints in PWL constraints

  • Fixed sign bug in translating MIN constraints that can lead to wrong answers

  • Fixed numerical issues with sin() and cos() nonlinear functions of global MINLP feature

  • Fixed bug in propagating nonlinear constraints of global MINLP feature

  • Fixed bug in handling POW constraint of global MINLP feature that could lead to wrong answers

  • Fixed bug in propagating nonlinear constraints in global MINLP feature that could lead to solutions with big violations

  • Fixed segmentation fault in global MINLP feature after linearizing a quadratic objective

  • Fixed segmentation fault with grbtune on Windows

  • Fixed automatic time limit computation for distributed tuning

  • Fixed small performance issue in the tuner with switching too late to tuning the run time instead of the gap

  • Fixed bug with the tuning tool ignoring constraint attributes for the tuning

  • Fixed bug with disregarding fixed parameter setting in remote tuning

Fixed issues in Gurobi 11.0.0#

Optimizer bug fixes#

  • Fixed logging from remote worker in Cluster Manager batch mode

  • Return error when referencing a constraint in a Column object that is not a linear constraint

  • Fixed numerical issue with small variable lower bound and variable upper bound constraints introduced to translate an SOS constraint

  • Fixed numerical issues in node presolve that could lead to wrong answers

  • Fixed non-deterministic behavior for MIP models without objective function caused by a heuristic running in parallel to the root node

  • Fixed wrong answer issue with discarding a slightly violated solution but still pruning the search tree

  • Fixed corner case that could lead to wrong declaration of infeasibility for models with piece-wise linear objective function

  • Fixed issue in piece-wise linear primal simplex algorithm that can lead to wrong answers

  • Fixed wrong answer issue for models that have multiple components after the root cut loop in which a component can be completely fixed

  • Fixed bug with user callback returning an error would not terminate the optimization

  • Fixed wrong conclusion of unboundedness for MIQCPs

  • Fixed infinite loop in simplex in a specific case of a bad basis for numerically unstable problems

  • Fixed numerical issue in knapsack cover cut separator that can lead to wrong answers

  • Fixed bug in bound propagation of logistic general function constraint

  • Fixed numerical issue for very big objective values in barrier SOCP solver that could lead to wrong answers for MIQCPs

  • Fixed issue with semi variables with negative lower bounds that appear in general constraints

  • Fixed performance issue with probing when presolve can significantly reduce the model size

  • Fixed numerical issue in McCormick relaxation for bilinear constraints when coefficients become very small

  • Fixed numerical issue in constraint strengthening when very big values are involved

  • Fixed issue with incompatible dual node presolve reductions that lead to wrong answers

  • Fixed numerical issue with an underflow in node presolve domain propagation that can lead to wrong answers

  • Use presos1bigm parameter instead of fixed constant in SOS translations of MIQCPs to avoid numerical issue

  • Fixed wrong declaration of convexity for piece-wise linear objectives that leads to wrong answers

  • Fixed numerical issue with QP simplex returning wrong objective after running into numerical issue and restarting with different method

  • Fixed numerical issue in cut lifting that could produce wrong cuts

  • Fixed possible infinite loop in MIQCP solving

  • Fixed segmentation fault when interrupting and resuming an LP solve that decided to use the explicit dual problem

  • Fixed issue that distributed MIP on multi-objective MIP used one less worker than available

  • Fixed possible segmentation fault in dependent row presolve reduction

  • Fixed potential segmentation fault for PreQLinearize=2 for quadratic constraints

  • Fixed very rare performance issue in LP sifting algorithm

Examples#

  • Fixed bug in the gc_pwl_func examples that misses to set FuncPieces to 1