I’m trying to optimize the absolute value of an affine function, for example, something like:

```
using JuMP
model = Model()
@variable(model, x)
@objective(model, Min, abs(x))
```

but i get

```
Closest candidates are:
abs(::Bool) at bool.jl:83
abs(::Float16) at float.jl:526
abs(::Float32) at float.jl:527
...
Stacktrace:
[1] top-level scope at /home/sobhan/.julia/packages/MutableArithmetics/ZGFsK/src/rewrite.jl:227
[2] top-level scope at /home/sobhan/.julia/packages/JuMP/MnJQc/src/macros.jl:762
```

do i really have to define another variable like this?

```
using JuMP
model = Model()
@variable(model, x)
@variable(model, abs_x)
@constraints(model, begin abs_x >= x; abs_x >= -x end)
@objective(model, Min, abs_x)
model
```

i’m on julia 1.4 and JuMP v0.21.2