# Cut generation not working lazy constraints - lagrangian relaxation

**URL:** <https://discourse.julialang.org/t/cut-generation-not-working-lazy-constraints-lagrangian-relaxation/9948>\
**Category:** Optimization (Mathematical)\
**Created:** [March 24, 2018, 6:24pm UTC](https://discourse.julialang.org/t/cut-generation-not-working-lazy-constraints-lagrangian-relaxation/9948 "2018-03-24T18:24:40Z")\
**Posts on this page:** 1\
**Showing post:** 7

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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:** [March 27, 2018, 9:54pm UTC](https://discourse.julialang.org/t/cut-generation-not-working-lazy-constraints-lagrangian-relaxation/9948/7 "2018-03-27T21:54:03Z")

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This is one reason that JuMP 0.19 will no longer support solver-independent callbacks – they aren’t solver independent. See:

> [@Cutting plane algorithm performance varies with Gurobi and CPLEX](https://discourse.julialang.org/t/cutting-plane-algorithm-performance-varies-with-gurobi-and-cplex/8597/2):
>
> Callbacks are tied in very deeply to how a MIP solver works, and they’re just not the same across solvers. (This took some experience to discover.) In JuMP 0.19 we will no longer be providing solver-independent callbacks for this reason; they create a false expectation that you can abstract away the solver when you implement the callbacks. The replacement will be solver-specific callbacks that expose the same interface as the low-level API.

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