# Re: \[AMPL 24420\] Solution Error Gurobi

**URL:** <https://discuss.ampl.com/t/re-ampl-24420-solution-error-gurobi/276>\
**Category:** Google Group Mirror\
**Created:** [December 16, 2022, 11:27pm UTC](https://discuss.ampl.com/t/re-ampl-24420-solution-error-gurobi/276 "2022-12-16T23:27:34Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [December 16, 2022, 11:27pm UTC](https://discuss.ampl.com/t/re-ampl-24420-solution-error-gurobi/276/1 "2022-12-16T23:27:34Z")

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AMPL’s presolve phase, which runs before your problem is sent to Gurobi, is reporting this error:

```auto
presolve: constraint Conic1[1] cannot hold:
        body <= -2.7832 cannot be >= -2.7832; difference = -4.44089e-16
Setting $presolve_eps >= 5.33e-16 might help.

```

Basically, presolve is telling you that there is a very slight infeasibility in your constraints. An infeasibility that small is not of any importance, so you should tell presolve to ignore it, by setting the presolve\_eps option to a small positive value – as the message suggests. For example, you could try

```auto
option presolve_eps 1.0e-15;

```

since Gurobi’s infeasibility tolerance is actually a lot greater than that.

---

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**Author:** ![phucdnguyen93](https://avatars.discourse-cdn.com/v4/letter/p/e68b1a/32.png) [@phucdnguyen93](https://discuss.ampl.com/u/phucdnguyen93)\
**Post date:** [December 19, 2022, 7:53am UTC](https://discuss.ampl.com/t/re-ampl-24420-solution-error-gurobi/276/2 "2022-12-19T07:53:04Z")

</div>

Hey Robert,

There was a bug in the setup of my codes as well. Sorted that out over the weekend and now the program runs fine.

Have a happy Christmas. 🙂

Regards,