• Gurobi Staff

Hi Carlos,

It's not uncommon for models with many integer variables (which are not binary variables in disguise) to struggle with finding solutions.  What are the lower and upper bounds on your integer variables?

As a first step can you try running your model with our No Relaxation (NoRel) heuristic?  Set NoRelHeurTime to an hour or two (perhaps longer if you are able to), and see how it goes.  How successful it is (if at all) can determine next steps.  When you do this also write out a mst file as it will probably be useful later to store any solution that NoRel finds.

- Riley

Thanks Riley!

I have 6 BoolVar and 2 NumVar.

The NumVar (both) have a [0,20000] bound.

So did what you suggested and got the following results after a 3-hour run.

    Nodes    |    Current Node    |     Objective Bounds      |     Work Expl Unexpl |  Obj  Depth IntInf | Incumbent    BestBd   Gap | It/Node Time     0     0 1.1141e+09    0 10538          - 1.1141e+09      -     - 1476s     0     0 1.1141e+09    0 10566          - 1.1141e+09      -     - 1527s     0     0 1.1141e+09    0 10401          - 1.1141e+09      -     - 1694s     0     0 1.1141e+09    0 9851          - 1.1141e+09      -     - 1745s     0     0 1.1143e+09    0 11528          - 1.1143e+09      -     - 3063s     0     0 1.1143e+09    0 10205          - 1.1143e+09      -     - 3128s     0     0 1.1145e+09    0 9990          - 1.1145e+09      -     - 3147s     0     0 1.1145e+09    0 9292          - 1.1145e+09      -     - 3254s     0     0 1.1145e+09    0 10241          - 1.1145e+09      -     - 3347s     0     0 1.1145e+09    0 10156          - 1.1145e+09      -     - 3395s     0     0 1.1145e+09    0 9859          - 1.1145e+09      -     - 3506s     0     0 1.1145e+09    0 9830          - 1.1145e+09      -     - 3554s     0     0 1.1145e+09    0 10019          - 1.1145e+09      -     - 3661s     0     0 1.1145e+09    0 10384          - 1.1145e+09      -     - 3777s     0     0 1.1149e+09    0 8820          - 1.1149e+09      -     - 4532s     0     0 1.1149e+09    0 9511          - 1.1149e+09      -     - 4571s     0     0 1.1178e+09    0 9998          - 1.1178e+09      -     - 5363s     0     0          -    0               - 1.1178e+09      -     - 10800sCutting planes:  Gomory: 3  Cover: 4  Implied bound: 1167  Clique: 585  MIR: 186  Flow cover: 224  Zero half: 43  RLT: 146  Relax-and-lift: 69  BQP: 29  PSD: 1Explored 1 nodes (3692511 simplex iterations) in 10800.04 seconds (22706.96 work units)Thread count was 8 (of 8 available processors)Solution count 0Time limit reachedBest objective -, best bound 1.117773368396e+09, gap -

• Gurobi Staff

Hi Carlos,

I have 6 BoolVar and 2 NumVar

I'm not sure what this means.  These are not Gurobi terms.

How did the NoRel heuristic perform?  That's the part of the log that's interesting at the moment.

- Riley