# Largest number of variables that SCS.jl can handle

**URL:** <https://discourse.julialang.org/t/largest-number-of-variables-that-scs-jl-can-handle/100929>\
**Category:** Optimization (Mathematical)\
**Tags:** question, package, jump\
**Created:** [June 28, 2023, 11:54am UTC](https://discourse.julialang.org/t/largest-number-of-variables-that-scs-jl-can-handle/100929 "2023-06-28T11:54:34Z")\
**Posts on this page:** 1\
**Showing post:** 11

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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:** [July 5, 2023, 2:39pm UTC](https://discourse.julialang.org/t/largest-number-of-variables-that-scs-jl-can-handle/100929/11 "2023-07-05T14:39:02Z")

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> problem: variables n: 18846055, constraints m: 56379024  
> cones: z: primal zero / dual free vars: 37612021  
> l: linear vars: 2  
> s: psd vars: 18767001, ssize: 1
> 
> nnz(A): 58322374

This is a _very_ large PSD problem. As you can see, this one solves in 4e4 seconds, so I assume it’s about the limit of what you can solve in a reasonable amount of time.

As a general rule of thumb, I tend to think of problems with \<10^4 variables as easy, 10^5 as getting a bit hard, 10^6 as hard, and 10^7 as very hard. 10^8 as nigh impossible.

Why is the problem so large? What are you modeling? Have you looked at ways to simplify the problem?

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