# Obtaining Irreducible Inconsistent Subsystem (IIS) with JumP - Gurobi

**URL:** <https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491>\
**Category:** Optimization (Mathematical)\
**Tags:** question, jump\
**Created:** [April 3, 2021, 11:04am UTC](https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491 "2021-04-03T11:04:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![priantop](https://avatars.discourse-cdn.com/v4/letter/p/e47774/32.png) [@priantop](https://discourse.julialang.org/u/priantop)\
**Post date:** [April 3, 2021, 11:04am UTC](https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491/1 "2021-04-03T11:04:03Z")

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Hi,

I am kind of new to Julia (+/- 3 months of usage)

I am trying to find which constraints are members of IIS of an Infeasible or Unbounded optimisation problem. For example, I have the following script

```julia
using JuMP, Gurobi
model = direct_model(Gurobi.Optimizer())

# defining variables
@variable(model, z)
@variable(model, x1[a=1:10, b=1:5] => 0)
@variable(model, x2[a=1:10, b=1:5, c=1:7] => 0)
# and so on...

# objective and constraints

@objective(model, Max, z)

@constraint(model, const1[a=1:10, b=1:5, c=1:7], equation1)
@constraint(model, const2[b=1:5, c=1:7], equation2)
# and so on...

optimize!(model)

if termination_status(model) == MOI.INFEASIBLE_OR_UNBOUNDED
    @assert termination_status(model) == MOI.INFEASIBLE_OR_UNBOUNDED
    compute_conflict!(model)
    MOI.get(model, MOI.ConstraintConflictStatus(), const1) 
    MOI.get(model, MOI.ConstraintConflictStatus(), const2) 
end

```

I want to know which constraint at which index is a member of IIS

However, it returns an error of

```julia
MethodError: no method matching get(::Model, ::MathOptInterface.ConstraintConflictStatus, ::Array{ConstraintRef{Model,MathOptInterface.ConstraintIndex{MathOptInterface.ScalarAffineFunction{Float64},MathOptInterface.EqualTo{Float64}},ScalarShape},3})

```

Am I doing something wrong with my script? I think I followed what the syntax should be according to JuMP manuals

I am using JuliaPro\_v1.53-1, JuMP v0.21.6, and Gurobi v0.9.11

Any help or suggestions are appreciated.

Thanks in advance

Cheers

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<div class="post-metadata">

**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [April 4, 2021, 10:32pm UTC](https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491/2 "2021-04-04T22:32:15Z")

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`const1` is an array. Use broadcasting:

```nohighlight
MOI.get.(model, MOI.ConstraintConflictStatus(), const1)

```

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<div class="post-metadata">

**Author:** ![priantop](https://avatars.discourse-cdn.com/v4/letter/p/e47774/32.png) [@priantop](https://discourse.julialang.org/u/priantop)\
**Post date:** [April 5, 2021, 9:27pm UTC](https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491/3 "2021-04-05T21:27:11Z")

</div>

Ah I see, Thank you very much!