# Optimization.jl Iterations

**URL:** <https://discourse.julialang.org/t/optimization-jl-iterations/107845>\
**Category:** Optimization (Mathematical)\
**Created:** [December 20, 2023, 10:40am UTC](https://discourse.julialang.org/t/optimization-jl-iterations/107845 "2023-12-20T10:40:17Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bdas123](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bdas123/32/32142_2.png) [@bdas123](https://discourse.julialang.org/u/bdas123)\
**Post date:** [December 20, 2023, 10:40am UTC](https://discourse.julialang.org/t/optimization-jl-iterations/107845/1 "2023-12-20T10:40:17Z")

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Hello, how do I extract the number of iterations from Optimization.jl (specifically the NLopt package)?

Here is a sample code

```julia
using Optimization, OptimizationNLopt, ModelingToolkit

function calc_sse(x0,p)
    return sum(x0) + a
end

x0 = zeros(2)
lower_bounds = zeros(2).-1
upper_bounds = zeros(2).+1
a = 2

p = [a]
f = OptimizationFunction(calc_sse, Optimization.AutoModelingToollkit(false,false))
prob = Optimization.OptimizationProblem(f, x0,p, lb = lower_bounds, ub = upper_bounds)
sol = solve(prob, NLopt.LD_LBFGS())

```

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<div class="post-metadata">

**Author:** ![mike.ingold](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mike.ingold/32/203749_2.png) [@mike.ingold](https://discourse.julialang.org/u/mike.ingold)\
**Post date:** [December 21, 2023, 2:18pm UTC](https://discourse.julialang.org/t/optimization-jl-iterations/107845/2 "2023-12-21T14:18:17Z")

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The function `solve` returns an `OptimizationSolution`, a data `struct`ure described here: [Optimization Solutions · Optimization.jl (sciml.ai)](https://docs.sciml.ai/Optimization/stable/API/optimization_solution/).

It sounds like you should be able to find that information in the `sol.stats` field.

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<div class="post-metadata">

**Author:** ![bdas123](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bdas123/32/32142_2.png) [@bdas123](https://discourse.julialang.org/u/bdas123)\
**Post date:** [December 21, 2023, 6:01pm UTC](https://discourse.julialang.org/t/optimization-jl-iterations/107845/3 "2023-12-21T18:01:56Z")

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Thank you!

My bad on not fully reading the documentation. Should probably do so before asking a question on here.

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<div class="post-metadata">

**Author:** ![mike.ingold](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mike.ingold/32/203749_2.png) [@mike.ingold](https://discourse.julialang.org/u/mike.ingold)\
**Post date:** [December 21, 2023, 6:16pm UTC](https://discourse.julialang.org/t/optimization-jl-iterations/107845/4 "2023-12-21T18:16:12Z")

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No problem! Glad I was able to help.