# How to set Cbc Parameters

**URL:** https://discourse.julialang.org/t/how-to-set-cbc-parameters/38516
**Category:** Optimization (Mathematical)
**Created:** [April 30, 2020, 11:29pm UTC](https://discourse.julialang.org/t/how-to-set-cbc-parameters/38516 "2020-04-30T23:29:28Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![lausilvag](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lausilvag/32/9778_2.png) [@lausilvag](https://discourse.julialang.org/u/lausilvag)
#### Post date: [April 30, 2020, 11:29pm UTC](https://discourse.julialang.org/t/how-to-set-cbc-parameters/38516/1 "2020-04-30T23:29:29Z")

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Hi  
I am trying to set parameters for Cbc Solver

```
Z_OP = Model(with_optimizer(Cbc.Optimizer))
    set_parameter(Z_OP, "preProcess", off)
    set_parameter(Z_OP, "CliqueCuts", Root)

```

error:  
UndefVarError: Off not defined  
UndefVarError: Root not defined

Does anyone know how to fix the error and where can I find updated information on the command lines?

Thank you

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### Author: ![Henrique\_Becker](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/henrique_becker/32/15443_2.png) [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)
#### Post date: [May 1, 2020, 12:15am UTC](https://discourse.julialang.org/t/how-to-set-cbc-parameters/38516/2 "2020-05-01T00:15:05Z")

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Have you defined the variables `off` and `Root`? Seems to me that you want to pass either Strings or some constant inside the `Cbc` module but is instead passing names of variables that do not exist in the scope instead.

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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: [May 1, 2020, 2:28am UTC](https://discourse.julialang.org/t/how-to-set-cbc-parameters/38516/3 "2020-05-01T02:28:33Z")

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Use

```nohighlight
set_parameter(Z_OP, "preProcess", "off")

```

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### Author: ![lausilvag](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lausilvag/32/9778_2.png) [@lausilvag](https://discourse.julialang.org/u/lausilvag)
#### Post date: [May 4, 2020, 10:28pm UTC](https://discourse.julialang.org/t/how-to-set-cbc-parameters/38516/4 "2020-05-04T22:28:58Z")

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thank you for your help! 🙂