# Add constraints in parallel

**URL:** <https://discourse.julialang.org/t/add-constraints-in-parallel/51382>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [December 7, 2020, 7:41am UTC](https://discourse.julialang.org/t/add-constraints-in-parallel/51382 "2020-12-07T07:41:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![cyanzhao42](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cyanzhao42/32/20035_2.png) [@cyanzhao42](https://discourse.julialang.org/u/cyanzhao42)\
**Post date:** [December 7, 2020, 7:41am UTC](https://discourse.julialang.org/t/add-constraints-in-parallel/51382/1 "2020-12-07T07:41:39Z")

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Hi all,

I am wondering can I add constraints to one model in parallel? The constraints is added via a for-loop.

Thanks!

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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:** [December 7, 2020, 8:32am UTC](https://discourse.julialang.org/t/add-constraints-in-parallel/51382/2 "2020-12-07T08:32:28Z")

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> can I add constraints to one model in parallel?

No. Adding a constraint is not threadsafe because it mutates a lot of internal state of the model.

This StackOverflow answer is a good summary of how you can use JuMP in parallel:

> <https://stackoverflow.com/questions/64177415/create-jump-model-with-multi-threading-in-julia>

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**Author:** ![cyanzhao42](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cyanzhao42/32/20035_2.png) [@cyanzhao42](https://discourse.julialang.org/u/cyanzhao42)\
**Post date:** [December 10, 2020, 6:39am UTC](https://discourse.julialang.org/t/add-constraints-in-parallel/51382/3 "2020-12-10T06:39:27Z")

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Thanks!