# Fixing vs Constraining a variable in JuMP

**URL:** <https://discourse.julialang.org/t/fixing-vs-constraining-a-variable-in-jump/27609>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [August 16, 2019, 10:35am UTC](https://discourse.julialang.org/t/fixing-vs-constraining-a-variable-in-jump/27609 "2019-08-16T10:35:23Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![ccoffrin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ccoffrin/32/400_2.png) [@ccoffrin](https://discourse.julialang.org/u/ccoffrin)\
**Post date:** [August 16, 2019, 4:43pm UTC](https://discourse.julialang.org/t/fixing-vs-constraining-a-variable-in-jump/27609/6 "2019-08-16T16:43:07Z")

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BTW Ipopt has special treatment of variables with the same upper and lower bounds. This option may be of interest, [https://www.coin-or.org/Ipopt/documentation/node44.html#opt:fixed\_variable\_treatment](https://www.coin-or.org/Ipopt/documentation/node44.html#opt:fixed_variable_treatment)

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