Errors when running JuMP examples from documentation (ERROR: LoadError: UndefVarError: optimize! not defined)

[Peter-Jolly]

Hi,

I have tried running several of the examples from the docs only to get the error that optimize! is undefined. Please see code taken from docs below. Hope someone can help? Probably need to inlcude another package?

Thanks,

Peter

import Pkg
Pkg.add("JuMP")
# Pkg.add("NLopt")
Pkg.add("Ipopt")
Pkg.add("Test")

using JuMP
import Ipopt
import Test

function example_qcp(; verbose = true)
    model = Model(Ipopt.Optimizer)
    set_silent(model)
    @variable(model, x)
    @variable(model, y >= 0)
    @variable(model, z >= 0)
    @objective(model, Max, x)
    @constraint(model, x + y + z == 1)
    @constraint(model, x * x + y * y - z * z <= 0)
    @constraint(model, x * x - y * z <= 0)
    optimize!(model)
    if verbose
        print(model)
        println("Objective value: ", objective_value(model))
        println("x = ", value(x))
        println("y = ", value(y))
    end
    Test.@test termination_status(model) == MOI.LOCALLY_SOLVED
    Test.@test primal_status(model) == MOI.FEASIBLE_POINT
    Test.@test objective_value(model) ≈ 0.32699 atol = 1e-5
    Test.@test value(x) ≈ 0.32699 atol = 1e-5
    Test.@test value(y) ≈ 0.25707 atol = 1e-5
    return
end

example_qcp()
ERROR: LoadError: UndefVarError: optimize! not defined
Stacktrace:
 [1] example_qcp(; verbose::Bool)
   @ Main c:\Users\peter\Documents\Julia_Code\MPC_Development\Quadratic_Optimization.jl:21
 [2] example_qcp()
   @ Main c:\Users\peter\Documents\Julia_Code\MPC_Development\Quadratic_Optimization.jl:12
 [3] top-level scope
   @ c:\Users\peter\Documents\Julia_Code\MPC_Development\Quadratic_Optimization.jl:36
in expression starting at c:\Users\peter\Documents\Julia_Code\MPC_Development\Quadratic_Optimization.jl:36

[blegat]

optimize! was added in JuMP v0.19, I would guess you are using an older version. Maybe another package like JuMPeR is holding JuMP's version back. Try using a local project with Pkg.activate(".") to avoid any conflicts between packages used by different projects

[Peter-Jolly]

Thanks for responding and help. I replaced all of the "import" statements with "using" and the program worked. Just to mention I am running the script using VScode under Windows 10 using Julia 1.6.2

using JuMP
using Ipopt
using Test