How to refer to a JuMP variable using a string when the model is defined in a module?

Specific Domains Optimization (Mathematical)
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1

Hello, in a JuMP model I need to fix some variables, and these variables to fix are defined in a dictionary.

This works:

using JuMP, Ipopt
fvars   = Dict{String,Float64}("c" => 5)
m = Model(Ipopt.Optimizer)
# [...]
@variable(m, c) 
for (k,v) in fvars
    fix(eval(Symbol(k)), v; force = true)
end
# [...]

However if I wrap the model in a module I got an UndefVarError:

module Foo 
using JuMP, Ipopt
function foo()
    fvars   = Dict{String,Float64}("c" => 5)
    m = Model(Ipopt.Optimizer)
    # [...]
    @variable(m, c) 
    for (k,v) in fvars
        fix(eval(Symbol(k)), v; force = true)
    end
    # [...]
end
end

ERROR: UndefVarError: cnot defined inMain.Foo``

I guess the “eval” somehow happens too early, is there any workaround ?

2

Actually the issue was that the model was in a function, not much that it was embedded in a module…

I solved by using

global c = @variable(m, c)

but I guess if there is a better way, as this may kill the performances of my program (not much of the solving the optimization itself)…