# Infeasibility on SCIP - Problem feasible in other solvers

**URL:** <https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507>\
**Category:** Optimization (Mathematical)\
**Tags:** question, jump\
**Created:** [April 30, 2020, 9:09pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507 "2020-04-30T21:09:20Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![Diego](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@Diego](https://discourse.julialang.org/u/Diego)\
**Post date:** [April 30, 2020, 9:09pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/1 "2020-04-30T21:09:20Z")

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Dear Team,

I have been trying SCIP but whatever I do it always returns an infeasibility.

Other solvers I have tried do deliver a solution.

The message I keep getting on an on for different problems is:

violation: right hand side is violated by 0.00533581525087357  
best solution is not feasible in original problem

What would you recommend?

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**Author:** ![Diego](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@Diego](https://discourse.julialang.org/u/Diego)\
**Post date:** [April 30, 2020, 9:46pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/2 "2020-04-30T21:46:02Z")

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This web may provide a valuable hint:

[https://stackoverflow.com/questions/22452332/obtain-best-feasible-solution-with-scip](https://stackoverflow.com/questions/22452332/obtain-best-feasible-solution-with-scip)

However, the SCIP.jl wrapper does not indicate how to enter “set emphasis feasibility”. Any suggestion?

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**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:** [May 1, 2020, 2:28am UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/3 "2020-05-01T02:28:06Z")

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Take a read of the first post in [Please read: make it easier to help you - #11](https://discourse.julialang.org/t/psa-make-it-easier-to-help-you/14757/11).

It’s easier to help if you provide a minimal piece of code that demonstrates the problem.

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**Author:** ![leethargo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/leethargo/32/6004_2.png) [@leethargo](https://discourse.julialang.org/u/leethargo)\
**Post date:** [May 1, 2020, 7:14am UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/4 "2020-05-01T07:14:40Z")

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Yeah, so SCIP.jl only supports setting parameters. To set an emphasis (which then sets multiple parameters), you would have to call the [underlying C function](https://github.com/SCIP-Interfaces/SCIP.jl/blob/ed32eefa8f5aa495215da7619dee3f2c6b44607f/src/wrapper/scip_param.jl#L165). That is, it’s not straight-forward to do currently.

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**Author:** ![Diego](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@Diego](https://discourse.julialang.org/u/Diego)\
**Post date:** [May 1, 2020, 9:11am UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/5 "2020-05-01T09:11:24Z")

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Let me then share the code I am using:

```julia
using JuMP # used for mathematical programming
using MathOptFormat
using MathOptInterface
using SCIP

mps_model = MathOptFormat.MPS.Model()
MOI.read_from_file(mps_model,string(path,"test_1.mps"))

ucf = Model(with_optimizer(SCIP.Optimizer))
MOI.copy_to(JuMP.backend(ucf),mps_model)
@time optimize!(ucf)

```

I have placed a set of three MPS files in WeTransfer to be able to reproduce the problem:

[https://we.tl/t-nHrmMNhben](https://we.tl/t-nHrmMNhben)

Thank you

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<div class="post-metadata">

**Author:** ![Diego](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@Diego](https://discourse.julialang.org/u/Diego)\
**Post date:** [May 1, 2020, 4:32pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/6 "2020-05-01T16:32:27Z")

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Any other idea to avoid SCIP to find the problem infeasible? It runs well on other solvers.

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**Author:** ![leethargo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/leethargo/32/6004_2.png) [@leethargo](https://discourse.julialang.org/u/leethargo)\
**Post date:** [May 1, 2020, 6:22pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/7 "2020-05-01T18:22:35Z")

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It might be best to ask on the SCIP mailing list.  
But from the message that you quote in your original post, it looks like SCIP actually finds a solution, but then discards it because the violation is beyond the tolerances.

So playing with `feastol` might help here.

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<div class="post-metadata">

**Author:** ![Diego](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@Diego](https://discourse.julialang.org/u/Diego)\
**Post date:** [May 1, 2020, 6:35pm UTC](https://discourse.julialang.org/t/infeasibility-on-scip-problem-feasible-in-other-solvers/38507/8 "2020-05-01T18:35:48Z")

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> [@leethargo](#):
>
> So playing with `feastol` might help here.

Already did play with feastol, unluckily it was infeasible always

Will reach out to SCIP mailing list

Thanks