# JuMP dual inside loop
**URL:** https://discourse.julialang.org/t/jump-dual-inside-loop/76895
**Category:** Optimization (Mathematical)
**Tags:** question, jump
**Created:** [February 22, 2022, 9:36am UTC](https://discourse.julialang.org/t/jump-dual-inside-loop/76895 "2022-02-22T09:36:19Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Mariana](https://discourse.julialang.org/u/Mariana)
#### Post date: [February 22, 2022, 9:36am UTC](https://discourse.julialang.org/t/jump-dual-inside-loop/76895/1 "2022-02-22T09:36:19Z")
Hello!
I am trying to run a code using the `dual` function from JuMP inside a loop, but I’m not getting the results I expected.
The code is a bit extensive, so I’ll try to put here the most relevant parts of the model for my question:
```julia
xx = [@variable(sub, [1:T, 1:nGen, 1:K+1]) for i = 1:3]
@constraints(sub, begin
DualFisherg, xx[1] .== xk[1]
DualFisherup, xx[2] .== xk[2]
DualFisherdn, xx[3] .== xk[3]
end)
for ω =2:S
for t=1:T
JuMP.set_normalized_rhs(eq35_bal3[t,3], d_hat[t, ω])
JuMP.set_normalized_rhs(eq36_bal3[t,3], d[t, ω])
for i=1:nGen
for k=1:K
if t > 1
JuMP.set_normalized_coefficient(eqld1[t,i,k], xx[1][t, i, k], -d[t-k, ω])
JuMP.set_normalized_coefficient(eqld2[t,i,k], xx[2][t, i, k], -d[t-k, ω])
JuMP.set_normalized_coefficient(eqld3[t,i,k], xx[3][t, i, k], -d[t-k, ω])
end
end
end
end
status = optimize!(sub)
Q += JuMP.objective_value(sub)/S
λg += JuMP.dual.(DualFisherg)./S
λup += JuMP.dual.(DualFisherup)./S
λdn += JuMP.dual.(DualFisherdn)./S
end
```
In this code, `S` is the number of scenarios I’m using. So, when I have more than one scenario, I change the right-hand side and the coefficients of some constraints, optimize the model, and update the objective value and the duals of three constraints.
The values of `Q` and `λg` in this code are being updated correctly when I have more than one scenario, but the other values (`λup` and `λdn`) are not. Any ideas why this happens?
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [February 22, 2022, 5:45pm UTC](https://discourse.julialang.org/t/jump-dual-inside-loop/76895/2 "2022-02-22T17:45:52Z")
Please provide a reproducible example. I can’t run your code so I can’t see the problem.
What is the error? Just a wrong result?
---
### Author:  [@Mariana](https://discourse.julialang.org/u/Mariana)
#### Post date: [February 23, 2022, 7:35pm UTC](https://discourse.julialang.org/t/jump-dual-inside-loop/76895/3 "2022-02-23T19:35:19Z")
It was just a wrong result, but I’ve already fixed it. Thanks!