Installation

For most projects, installation is one command. oximo includes the Highs solver by default, so you can build and solve linear, mixed-integer linear, and quadratic models without installing a solver or obtaining a license.

This site is a guide for tutorials and worked examples. For the complete API reference, see docs.rs/oximo.

🔗Start here

oximo requires Rust 1.85 or later (edition 2024). Install Rust with rustup if you do not already have it.

Create a project and add oximo:

cargo new my-oximo-model --edition 2024
cd my-oximo-model
cargo add oximo

That is enough to use Highs and write models to MPS, LP, or NL files. The bundled HiGHS build needs a C compiler:

• On Windows, install the MSVC C++ build tools,
• on macOS, run xcode-select --install,
• on Linux, install your distribution's standard C/C++ build tools.

Next, follow the Quickstart to create and solve your first model. If the project builds and the Quickstart prints an objective value, your installation is ready.

🔗Choose another backend

If you need another backend, you can use the provided features flags.

The Solvers guide compares model-kind support, shows the different requirements of each backend, and covers external solver setup. It is the best place to choose an engine when you are unsure.

For example, to add the Clarabel backend:

cargo add oximo --features clarabel --no-default-features

Or, in Cargo.toml:

[dependencies]
oximo = { version = "0.5", features = ["clarabel"], default-features = false }

🔗Minimal builds

The default highs and io features are convenient for most users. If you want to avoid compiling bundled HiGHS, turn them off explicitly and select the backend you want:

[dependencies]
oximo = { version = "0.5", default-features = false, features = ["clarabel"] }

With no solver feature, you can still construct models. You will need a solver feature before solving them.

🔗Advanced: exact nonlinear derivatives

pounce uses finite-difference derivatives for nonlinear expressions by default. The nightly-only pounce-enzyme feature provides exact gradients, Jacobians, and Hessians through Enzyme. Use it for nonlinear POUNCE models when your toolchain can support it. It is highly recommended to use it.

It requires a nightly Rust toolchain with the enzyme component, RUSTFLAGS="-Zautodiff=Enable", and a fat-LTO profile. The oximo workspace provides an enzyme profile:

RUSTFLAGS="-Zautodiff=Enable" cargo +nightly build --profile enzyme --features pounce-enzyme

See the Enzyme installation instructions for configuring the toolchain.

🔗Feature reference

Feature	Included by default	Purpose
highs	yes	Bundled Highs solver for LP, MILP, and QP.
io	yes	MPS, LP, and NL file writers.
baron	no	Baron global-optimization backend.
clarabel	no	Pure-Rust Clarabel solver for LP, QP, and SOCP.
clarabel-faer	no	Use Clarabel's faer linear-algebra backend.
gurobi	no	Gurobi backend.
gams	no	Gams bridge.
pounce	no	Pure-Rust Pounce solver for continuous nonlinear models.
pounce-enzyme	no	Exact Enzyme derivatives for POUNCE; requires nightly Rust.
mosek	no	Mosek backend for MOSEK 11.2.