# \`dualize()\` cannot take \`ignore\_objective\` argument
**URL:** https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650
**Category:** Optimization (Mathematical)
**Tags:** dualization
**Created:** [May 10, 2023, 10:46pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650 "2023-05-10T22:46:18Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@g001234](https://discourse.julialang.org/u/g001234)
#### Post date: [May 10, 2023, 10:46pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650/1 "2023-05-10T22:46:18Z")
When using Dualization.jl to dualize an LP, I used the `ignore_objective` argument to turn off the objective. However, I received the following error:
````julia
ERROR: MethodError: no method matching dualize(::Model, ::Nothing; dual_names=DualNames("dual_", "dual_", "", ""), ignore_objective=true, consider_constrained_variables=false)
Closest candidates are:
dualize(::Model, ::Any; dual_names) at /Users/chengguo/.julia/packages/Dualization/cjSlF/src/dualize.jl:197 got unsupported keyword arguments "ignore_objective", "consider_constrained_variables"
dualize(::Model) at /Users/chengguo/.julia/packages/Dualization/cjSlF/src/dualize.jl:197 got unsupported keyword arguments "dual_names", "ignore_objective", "consider_constrained_variables"
Stacktrace:
[1] kwerr(::NamedTuple{(:dual_names, :ignore_objective, :consider_constrained_variables), Tuple{DualNames, Bool, Bool}}, ::Function, ::Model, ::Nothing)
@ Base ./error.jl:157
[2] top-level scope
@ ~/Dropbox/codes_sync/expansion_mechanism/codes/jl_code/try_dualize.jl:25```
````
Here is my code:
```julia
using JuMP, Dualization
m = Model()
@variable(m, x >= 0)
@variable(m, y >= 0)
@constraints(m, begin
con1, 3 * x + 2 * y >= 9
con2, 2 * x + y >= 6
ub, x <= 2
end)
@objective(m, Min, 8 * x + 10 * y)
dual_m = Dualization.dualize(
m;
dual_names = DualNames("dual_", "dual_"),
ignore_objective = true,
consider_constrained_variables = false,
)
```
I saw the same usage in the source code of BilevelJuMP.jl, so I am confused why I got the error. Any insights?
Version Info:
Julia: 1.6.3
JuMP: 1.11.0
Dualization.jl: 0.5.7
---
### Author:  [@guilhermebodin](https://discourse.julialang.org/u/guilhermebodin)
#### Post date: [May 10, 2023, 10:59pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650/2 "2023-05-10T22:59:24Z")
Hi, @g001234 thanks for posting the question. I added the post as an issue on the Dualization repo. I should only be able to investigate it next week but maybe some other maintainers can help you in the meantime.
---
### Author:  [@g001234](https://discourse.julialang.org/u/g001234)
#### Post date: [May 10, 2023, 11:10pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650/3 "2023-05-10T23:10:11Z")
Thank you for the fast reply, @guilhermebodin ! Would you think any version of Dualization.jl does not have this issue? I am thinking about pinning it to an older version as a quick fix.
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [May 10, 2023, 11:15pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650/4 "2023-05-10T23:15:49Z")
Hi Cheng, let me take a look.
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [May 10, 2023, 11:28pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650/5 "2023-05-10T23:28:15Z")
See [Fix dualizing JuMP model with kwargs by odow · Pull Request #159 · jump-dev/Dualization.jl · GitHub](https://github.com/jump-dev/Dualization.jl/pull/159)
---
### Author:  [@g001234](https://discourse.julialang.org/u/g001234)
#### Post date: [May 10, 2023, 11:35pm UTC](https://discourse.julialang.org/t/dualize-cannot-take-ignore-objective-argument/98650/6 "2023-05-10T23:35:23Z")
Thank you so much for fixing this, Oscar! I had thought it’s something on my end so I didn’t open an issue. The update makes sense : )