# SCIP Concurrency (Multi-threading)

**URL:** <https://discourse.julialang.org/t/scip-concurrency-multi-threading/80814>\
**Category:** Optimization (Mathematical)\
**Tags:** package, jump\
**Created:** [May 10, 2022, 2:21pm UTC](https://discourse.julialang.org/t/scip-concurrency-multi-threading/80814 "2022-05-10T14:21:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![this\_josh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/this_josh/32/42679_2.png) [@this\_josh](https://discourse.julialang.org/u/this_josh)\
**Post date:** [May 10, 2022, 2:21pm UTC](https://discourse.julialang.org/t/scip-concurrency-multi-threading/80814/1 "2022-05-10T14:21:37Z")

</div>

As of version 4 [SCIP supports concurrency](https://www.scipopt.org/doc-5.0.1/html/CONCSCIP.php). It mentions here that the option `"parallel/maxnthreads"` must be set as appropriate, it also mentions that SCIP must be compiled differently to leverage this functionality and that [`SCIPsolveParallel`](https://www.scipopt.org/doc-5.0.1/html/group__PublicSolveMethods.php#ga34745068ea50435c98281a445ef53533) should be called instead of `optimize` in the SCIP shell.

I’m using a Mac, so as described in the [SCIP.jl read me](https://github.com/scipopt/SCIP.jl/blob/master/README.md) I don’t need to install SCIP separately.

Currently to use SCIP I’m running

```julia
using JuMP
using SCIP
model = Model(optimizer_with_attributes(SCIP.Optimizer, "parallel/maxnthreads"=>10)

```

which doesn’t cause any error, but also doesn’t seem to use multi threading. Given I’m not compiling SCIP myself and using it via JuMP \> SCIP.jl how can I use multi threading as there are three steps required to use multi-threading when using SCIP directly?

1. Compile with a flag for multi\_threading (I’m unsure whether I have SCIP installed this way)
2. Set the number of threads attribute
3. Call `SCIPsolveParallel` instead of `optimize`

---

<div class="post-metadata">

**Author:** ![jd-foster](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jd-foster/32/35824_2.png) [@jd-foster](https://discourse.julialang.org/u/jd-foster)\
**Post date:** [May 10, 2022, 2:44pm UTC](https://discourse.julialang.org/t/scip-concurrency-multi-threading/80814/2 "2022-05-10T14:44:12Z")

</div>

(Moved this to the Mathematical Optimization category.)

FYI: You can see how the SCIP binary is built here;

> <https://github.com/JuliaPackaging/Yggdrasil/blob/3ab5dd7ded15a37d1b691a47d14d4319ca4beb68/S/SCIP/build_tarballs.jl>