Self reference in @expression statement in Julia

Question

I am still quite new in Julia but I was wondering if there is a way to make a self reference in an @expression statement in JuMP.

For instance I would like to be able to make this statement:

n = 3 @expression(model_opt, D[i=1:9], i>n ? D[i-n] : i)

which would define a vector D as follows

D = [1 2 3 1 2 3 1 2 3]

But for the moment Julia just tells me that D is not known

UndefVarError: D not defined

Thank you in advance for your help!

Answer 1

Welcome to Julia, you're in for a ride. No, that is not supported. You can write a for loop instead:

D = []
n = 3
for i in 1:9
    push!(D, @expression(model_opt, i>n ? D[i-n] : i))
end