# Why Nelder-Mead minimization without minimal property check?

**URL:** <https://discourse.julialang.org/t/why-nelder-mead-minimization-without-minimal-property-check/102236>\
**Category:** Optimization (Mathematical)\
**Tags:** optimization\
**Created:** [July 29, 2023, 12:45pm UTC](https://discourse.julialang.org/t/why-nelder-mead-minimization-without-minimal-property-check/102236 "2023-07-29T12:45:08Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [July 29, 2023, 12:55pm UTC](https://discourse.julialang.org/t/why-nelder-mead-minimization-without-minimal-property-check/102236/2 "2023-07-29T12:55:13Z")

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> [@dietrich](#):
>
> Why did you not include a check of the minimum property, as in early fortran Nelder-Mead codes?

The real question is, why include Nelder–Mead? Why use it? It’s an obsolete algorithm that is not guaranteed to converge, and there are plenty of other derivative-free local-optimization algorithms these days. There isn’t an easy check that ensures that it is globally convergent (i.e. always converges to some local minimum, not necessarily to a global minimum) — there are globally convergent Nelder–Mead variants, but they involve much more substantial changes IIRC.

I included it in NLopt, but really only for comparison purposes, and I recommend that people only use it for this purpose. I don’t know why Optim.jl uses it by default for gradient-free problems.

> [@dietrich](#):
>
> the Powell like minimization routines (without gradients) of Julia are at least 100 times slower than the f90 version and were too slow to be useful for me.

What “Powell-like” routine are you referring to? I don’t see one in Optim.jl? (When you say “100 times slower”, do you mean that it converges in 100x more iterations, or that each iteration is 100x slower?)

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