# Comparing non-linear least squares solvers

**URL:** <https://discourse.julialang.org/t/comparing-non-linear-least-squares-solvers/104752>\
**Category:** Optimization (Mathematical)\
**Tags:** nonlinear, nonlinear-optimizati\
**Created:** [October 9, 2023, 1:37pm UTC](https://discourse.julialang.org/t/comparing-non-linear-least-squares-solvers/104752 "2023-10-09T13:37:45Z")\
**Posts on this page:** 1\
**Showing post:** 16

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**Author:** ![user664303](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/user664303/32/37843_2.png) [@user664303](https://discourse.julialang.org/u/user664303)\
**Post date:** [October 10, 2023, 1:34pm UTC](https://discourse.julialang.org/t/comparing-non-linear-least-squares-solvers/104752/16 "2023-10-10T13:34:51Z")

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> [@kellertuer](#):
>
> I would be interested how (and which). non-Euclidean variables are realised in NLLSsolver.jl

I’ve implemented 3D rotation matrices ([see the implementation here](https://github.com/ojwoodford/NLLSsolver.jl/blob/ced2471c9225b176de4c800eca34fb903e1bb3f6/src/visualgeometry/geometry.jl#L56)) and bounded variables (as [we discussed before](https://discourse.julialang.org/t/a-new-solver-for-robustified-non-linear-least-squares-problems-with-non-euclidean-variables/96085/4)), but it’s easy to add your own. It should be very straightforward to use variables from `Manifolds.jl` in `NLLSsolver.jl`. You just need to overload the `NLLSsolver.update` method for the particular variable type.

I’m happy to discuss it further. Please message me direct.

> [@kellertuer](#):
>
> `Manopt.jl` can do least squares on arbitrary manifolds (those from `Manifolds.jl`)

I’m slowly adding more solvers. I may try to add that one. But it’s a Euclidean problem.

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