# Potential Bug in Optimization.jl
**URL:** https://discourse.julialang.org/t/potential-bug-in-optimization-jl/108066
**Category:** Optimization (Mathematical)
**Created:** [December 26, 2023, 6:41pm UTC](https://discourse.julialang.org/t/potential-bug-in-optimization-jl/108066 "2023-12-26T18:41:11Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@bdas123](https://discourse.julialang.org/u/bdas123)
#### Post date: [December 26, 2023, 6:41pm UTC](https://discourse.julialang.org/t/potential-bug-in-optimization-jl/108066/1 "2023-12-26T18:41:11Z")
Here is my code which utilizes Optimization.jl and ModelingToolkit.jl:
```julia
using BenchmarkTools, Optimization, OptimizationNLopt, ModelingToolkit
function func_1(x0,p)
sse = sum(x0) + p[1]
return sse
end
function cb(p,l)
println("Running callback")
display(p)
display(l)
return false
end
x0 = ones(2)
p = [2]
lower_bounds = zeros(2).-2
upper_bounds = zeros(2).+2
func = OptimizationFunction(func_1, AutoModelingToolkit(false,false))
prob = Optimization.OptimizationProblem(func,x0,p,lb = lower_bounds, ub = upper_bounds)
@time sol = solve(prob, NLopt.LD_LBFGS(), callback=cb, reltol = 1e2)
```
Code works fine, but the following line does not output anything:
```julia
sol.stats
```
---
### Author:  [@Vaibhavdixit02](https://discourse.julialang.org/u/Vaibhavdixit02)
#### Post date: [December 26, 2023, 7:17pm UTC](https://discourse.julialang.org/t/potential-bug-in-optimization-jl/108066/2 "2023-12-26T19:17:21Z")
>
>
> \`\`\` Julia
> rosenbrock(x, p) = (p\[1\] - x\[1\])^2 + p\[2\] \* (x\[2\] - x\[1\]^2)^2
> x0 = z…eros(2)
> p = \[1.0, 100.0\]
> f = OptimizationFunction(rosenbrock, Optimization.AutoForwardDiff())
> prob = Optimization.OptimizationProblem(f, x0, p, lb = \[-1.0, -1.0\], ub = \[1.0, 1.0\])
> sol = solve(prob, NLopt.LD\_LBFGS())
> \`\`\`
> This is the example from NLopt.jl tutorial page. I would expect to have sol.stats to work, for example, showing me how many iterations it takes, and so on. But it shows nothing. Any help is appreciated. Thanks.
`sol.stats` isn’t implemented yet