# Levenberg-Marquardt in Optim.jl 0.9.0

**URL:** https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565
**Category:** Optimization (Mathematical)
**Created:** [June 30, 2017, 2:14pm UTC](https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565 "2017-06-30T14:14:40Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![mzaffalon](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mzaffalon/32/214168_2.png) [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)
#### Post date: [June 30, 2017, 2:14pm UTC](https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565/1 "2017-06-30T14:14:40Z")

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I am trying to fix this [mexjulia example](https://github.com/twadleigh/mexjulia/blob/66b50cd2c342fdfb60eb57f56056a67fd049671d/examples/lmdif.jl) and I cannot figure out what to replace `levenberg_marquardt` with. In particular, `levenberg_marquardt` returns a vector of residuals of length `m` but as far as I can see, all of the Optim.jl 0.9.0 optimization methods require the function to minimize to return a scalar.

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### Author: ![abieler](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abieler/32/2693_2.png) [@abieler](https://discourse.julialang.org/u/abieler)
#### Post date: [June 30, 2017, 2:59pm UTC](https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565/2 "2017-06-30T14:59:38Z")

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I think Levenberg-Marquardt moved to LsqFit.jl

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### Author: ![mzaffalon](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mzaffalon/32/214168_2.png) [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)
#### Post date: [June 30, 2017, 3:16pm UTC](https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565/3 "2017-06-30T15:16:17Z")

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Thank you.

[https://github.com/twadleigh/mexjulia/pull/45](https://github.com/twadleigh/mexjulia/pull/45)

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### Author: ![pkofod](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pkofod/32/2179_2.png) [@pkofod](https://discourse.julialang.org/u/pkofod)
#### Post date: [July 3, 2017, 9:22pm UTC](https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565/4 "2017-07-03T21:22:29Z")

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This is correct. We had a pretty long deprecation period though. Happy to help if something isn’t working out as expected!

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### Author: ![mzaffalon](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mzaffalon/32/214168_2.png) [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)
#### Post date: [July 4, 2017, 4:41am UTC](https://discourse.julialang.org/t/levenberg-marquardt-in-optim-jl-0-9-0/4565/5 "2017-07-04T04:41:38Z")

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The deprecation works only if one happens to use the function during the deprecation period and I didn’t. I remember reading about the splitting of the two packages, but I could not find that announcement.