# Modify equality constraints in JuMP

**URL:** <https://discourse.julialang.org/t/modify-equality-constraints-in-jump/10982>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [May 18, 2018, 9:10am UTC](https://discourse.julialang.org/t/modify-equality-constraints-in-jump/10982 "2018-05-18T09:10:05Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![pierre-haessig](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pierre-haessig/32/217129_2.png) [@pierre-haessig](https://discourse.julialang.org/u/pierre-haessig)\
**Post date:** [May 18, 2018, 9:10am UTC](https://discourse.julialang.org/t/modify-equality-constraints-in-jump/10982/1 "2018-05-18T09:10:05Z")

</div>

Hello,

In JuMP 0.18 documentation on [Problem Modification](http://www.juliaopt.org/JuMP.jl/0.18/probmod.html#modifying-constraints), I read that

> JuMP does not currently support changing constraint coefficients. For less-than and greater-than constraints, the right-hand-side can be changed.

However, does this feature extends to equality constraints ? Or should I convert my equality contraints to two inequalities ?

Would this conversion impact the performance? (I’m solving LPs with Clp).

Or maybe I should wait for the transition to MathOptInterface (cf. answer in [Updating data in JuMP constraints iteratively? - #7 by miles.lubin](https://discourse.julialang.org/t/updating-data-in-jump-constraints-iteratively/5467/7))

Best,  
Pierre

---

<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 18, 2018, 9:54am UTC](https://discourse.julialang.org/t/modify-equality-constraints-in-jump/10982/2 "2018-05-18T09:54:02Z")

</div>

Have you tried? It should work. The docs probably need updating.

---

<div class="post-metadata">

**Author:** ![pierre-haessig](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pierre-haessig/32/217129_2.png) [@pierre-haessig](https://discourse.julialang.org/u/pierre-haessig)\
**Post date:** [May 25, 2018, 4:12pm UTC](https://discourse.julialang.org/t/modify-equality-constraints-in-jump/10982/3 "2018-05-25T16:12:10Z")

</div>

Thanks for the tip! I made a small test with a basic LP and it works.

[https://gist.github.com/pierre-haessig/a00f97c0c9d46e24c32afba4625700ee](https://gist.github.com/pierre-haessig/a00f97c0c9d46e24c32afba4625700ee)

I’ve not yet made performance comparisons though.

Best,  
Pierre