# How to add Integer contraint to variables using the @variables macro?

**URL:** <https://discourse.julialang.org/t/how-to-add-integer-contraint-to-variables-using-the-variables-macro/27500>\
**Category:** Optimization (Mathematical)\
**Tags:** jump\
**Created:** [August 13, 2019, 2:39pm UTC](https://discourse.julialang.org/t/how-to-add-integer-contraint-to-variables-using-the-variables-macro/27500 "2019-08-13T14:39:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [August 13, 2019, 2:39pm UTC](https://discourse.julialang.org/t/how-to-add-integer-contraint-to-variables-using-the-variables-macro/27500/1 "2019-08-13T14:39:27Z")

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To bound a variable to be integer I can use `integer=true`, e.g. `@variable(m, 0 <= p, integer=true, start=1)`, but how to do that when I use the `@variables` macro?

I did try as such, but it is not recognised (also `base_name` it doesn’t work):

```julia
@variables trmodel begin
    x[p in plants, m in markets] >= 0
    base_name="shipment quantities in cases" # doesn't work
    integer=true # doesn't work
end

```

---

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**Author:** ![blegat](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/blegat/32/217090_2.png) [@blegat](https://discourse.julialang.org/u/blegat)\
**Post date:** [August 13, 2019, 3:02pm UTC](https://discourse.julialang.org/t/how-to-add-integer-contraint-to-variables-using-the-variables-macro/27500/2 "2019-08-13T15:02:49Z")

</div>

You can do

```julia
@variables trmodel begin
    x[p in plants, m in markets] >= 0, (base_name="shipment quantities in cases", integer=true)
end

```

or

```julia
@variables trmodel begin
    x[p in plants, m in markets] >= 0, (integer=true,)
end

```

if there is only one keyword argument.  
See [https://github.com/JuliaOpt/JuMP.jl/blob/79a4fe4d4fc11bc96b62a88b085734429a833dd2/src/macros.jl#L847-L848](https://github.com/JuliaOpt/JuMP.jl/blob/79a4fe4d4fc11bc96b62a88b085734429a833dd2/src/macros.jl#L847-L848)