# Callbacks - Accessing Gurobi specific functionality

**URL:** <https://discourse.julialang.org/t/callbacks-accessing-gurobi-specific-functionality/98560>\
**Category:** Optimization (Mathematical)\
**Created:** [May 9, 2023, 4:02pm UTC](https://discourse.julialang.org/t/callbacks-accessing-gurobi-specific-functionality/98560 "2023-05-09T16:02:55Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Sokar](https://avatars.discourse-cdn.com/v4/letter/s/e79b87/32.png) [@Sokar](https://discourse.julialang.org/u/Sokar)\
**Post date:** [May 9, 2023, 4:02pm UTC](https://discourse.julialang.org/t/callbacks-accessing-gurobi-specific-functionality/98560/1 "2023-05-09T16:02:55Z")

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Hi everyone.

Working on my master thesis project, I have run into some problems using JuMP and Gurobi. I need to use Gurobi specific callback functionality, but as far as I can tell, this requires me to construct my model in direct mode (using direct\_model()). However, I cannot find a way to do this, while also reusing my Gurobi environment. Is there a way to use Gurobi callback functionality, without using direct\_model, or reuse the gurobi environment with direct\_model?

Kind regards,  
Nicolai

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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:** [May 9, 2023, 8:37pm UTC](https://discourse.julialang.org/t/callbacks-accessing-gurobi-specific-functionality/98560/2 "2023-05-09T20:37:01Z")

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Use:

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

```

I’ll update the documentation.

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<div class="post-metadata">

**Author:** ![Sokar](https://avatars.discourse-cdn.com/v4/letter/s/e79b87/32.png) [@Sokar](https://discourse.julialang.org/u/Sokar)\
**Post date:** [May 10, 2023, 5:20am UTC](https://discourse.julialang.org/t/callbacks-accessing-gurobi-specific-functionality/98560/3 "2023-05-10T05:20:21Z")

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I could have sworned I had tried just that, but it works just fine. Thanks a bunch.