# \#surrogates

**URL:** https://discourse.julialang.org/tag/surrogates/1914.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

---

## [Surrogate with derivatives](https://discourse.julialang.org/t/surrogate-with-derivatives/137277)

<div class="topic-metadata">

**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 6\
**Last updated:** [May 26, 2026, 11:42am UTC](https://discourse.julialang.org/t/surrogate-with-derivatives/137277 "2026-05-26T11:42:02Z")

</div>

I am solving an implicit function f(x, y(x)) = 0 with x, y \\in \\mathbb{R}^n (typical n is 50–200), using iterative methods (trust region), at many x’s. This question is about finding a good initial value y\_0(x) for ea…