# The Uno (Unifying Nonlinear Optimization) solver

**URL:** https://discourse.julialang.org/t/the-uno-unifying-nonlinear-optimization-solver/115883
**Category:** Optimization (Mathematical)
**Tags:** nonlinear-optimizati, nonconvex-optimizati, nonlinear-programmin, sqp
**Created:** [June 19, 2024, 8:23pm UTC](https://discourse.julialang.org/t/the-uno-unifying-nonlinear-optimization-solver/115883 "2024-06-19T20:23:45Z")
**Posts on this page:** 3
**Page:** 4

<div class="post-metadata">

### Author: ![cvanaret](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cvanaret/32/11594_2.png) [@cvanaret](https://discourse.julialang.org/u/cvanaret)
#### Post date: [June 10, 2026, 8:48am UTC](https://discourse.julialang.org/t/the-uno-unifying-nonlinear-optimization-solver/115883/62 "2026-06-10T08:48:03Z")

</div>

Our article [Implementing a unified solver for nonlinearly constrained optimization](https://link.springer.com/article/10.1007/s12532-026-00310-9) was finally published (open access) in Mathematical Programming Computation 🥳

It was a pleasure to meet some of you at JuMP-dev/SIAM OP 🙂

---

<div class="post-metadata">

### Author: ![cvanaret](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cvanaret/32/11594_2.png) [@cvanaret](https://discourse.julialang.org/u/cvanaret)
#### Post date: [July 16, 2026, 10:36am UTC](https://discourse.julialang.org/t/the-uno-unifying-nonlinear-optimization-solver/115883/63 "2026-07-16T10:36:41Z")

</div>

Uno v2.8.0 / UnoSolver.jl v0.3.6 introduces an automatic preset that picks between SQP and barrier based on the problem size. It also enables dynamic loading for the HSL linear solvers and a new interface to HSL MA86.

@amontoison and I also published a [software article](https://joss.theoj.org/papers/10.21105/joss.10229) in JOSS ✌

---

<div class="post-metadata">

### Author: ![cvanaret](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cvanaret/32/11594_2.png) [@cvanaret](https://discourse.julialang.org/u/cvanaret)
#### Post date: [September 10, 2026, 10:08am UTC](https://discourse.julialang.org/t/the-uno-unifying-nonlinear-optimization-solver/115883/64 "2026-09-10T10:08:44Z")

</div>

[Uno v2.9.0](https://github.com/cvanaret/Uno/releases/tag/v2.9.0) / UnoSolver.jl v0.3.7 is out with substantial improvements to its barrier implementation. It now solves **45/47 instances on the [Mittelmann benchmark](https://plato.asu.edu/ftp/ampl-nlp.html)** in about the same time as IPOPT 🙂

[Previous page](https://discourse.julialang.org/t/the-uno-unifying-nonlinear-optimization-solver/115883.md?page=3)