RROR: LoadError: Gurobi Error 10015: Cannot compute IIS on a feasible model

Answered

manoj kumar

August 24, 2021 19:10

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Hi

 

I tried to remove objective function and getting the following log

 

WARNING: redefining constant Gurobix

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Academic license - for non-commercial use only - expires 2021-08-28
Gurobi Optimizer version 9.1.2 build v9.1.2rc0 (win64)
Thread count: 4 physical cores, 8 logical processors, using up to 8 threads
Optimize a model with 47415 rows, 45210 columns and 243234 nonzeros
Model fingerprint: 0x811e2488
Variable types: 0 continuous, 45210 integer (720 binary)
Coefficient statistics:
Matrix range [1e-01, 5e+05]
Objective range [0e+00, 0e+00]
Bounds range [0e+00, 0e+00]
RHS range [1e+00, 5e+05]
Found heuristic solution: objective 0.0000000

Explored 0 nodes (0 simplex iterations) in 0.03 seconds
Thread count was 1 (of 8 available processors)

Solution count 1: 0

Optimal solution found (tolerance 1.00e-04)
Best objective 0.000000000000e+00, best bound 0.000000000000e+00, gap 0.0000%

User-callback calls 22, time in user-callback 0.00 sec

=================================pppppppppppppppppppp
statusOPTIMAL
Found heuristic solution: objective 0.0000000

Explored 0 nodes (0 simplex iterations) in 0.03 seconds
Thread count was 1 (of 8 available processors)

Solution count 1: 0

Optimal solution found (tolerance 1.00e-04)
Best objective 0.000000000000e+00, best bound 0.000000000000e+00, gap 0.0000%
IIS runtime: 0.03 seconds
ERROR: LoadError: Gurobi Error 10015: Cannot compute IIS on a feasible model
Stacktrace:
[1] _check_ret at C:\Users\manojkumar.ram\.julia\packages\Gurobi\HtUHB\src\MOI_wrapper.jl:306 [inlined]
[2] compute_conflict!(::Gurobi.Optimizer) at C:\Users\manojkumar.ram\.julia\packages\Gurobi\HtUHB\src\MOI_wrapper.jl:3389
[3] top-level scope at C:\Users\manojkumar.ram\Desktop\shweta\code\code.jl:541
in expression starting at C:\Users\manojkumar.ram\Desktop\shweta\code\code.jl:541

any idea how to check whether the model is infeasible or unbounded. 

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• Official comment

  

  Gwyneth Butera

  • Gurobi Staff

  August 25, 2021 14:09

  For further information, you can have a look at our Knowledge Base article : How do I resolve the error "Model is infeasible or unbounded"?
• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  June 23, 2025 02:49 Edited

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
• 

  Alison Cozad

  • Gurobi Staff

  August 24, 2021 20:36

  There are a couple of ways to find the status of a solved model:

  1. In the log output:  In your case, the output it says "Optimal solution found (tolerance 1.00e-04)". So the model is not infeasible or unbounded.  If it were, you would see "Model is infeasible or unbounded".
  2. Status flag: The model will have a model.Status attribute that will return a Status Code.  If model.status is equal to GRB.INF_OR_UNBD (4), GRB.UNBOUNDED (5), or GRB.INFEASIBLE (3) then it is infeasible or unbounded.

  There is a good example of using the model status to determine whether or not to run IIS in lp.py.

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