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Uno Uno logo

CRAN status R-universe version R-CMD-check

We provide R bindings to Uno (Unifying Nonlinear Optimization), a C++ solver for nonlinearly constrained optimization, via Uno’s C API. The interface allows you to describe a nonlinear program with R callbacks for objective, gradient, constraints, Jacobian and Lagrangian Hessian and Uno solves it. This is the R analog of the unopy Python binding, intended as the nonlinear (DNLP) solver backend for CVXR.

Two solver paths are provided:

Installation

Install from CRAN as usual or from the repo via:

# install.packages("remotes")
remotes::install_github("bnaras/Uno")

A C++17 compiler and CMake (>= 3.16) are required for source builds as the package builds the underlying Uno from source. HiGHS comes from the highs dependency (version 1.15.1-2 or later, which exports HiGHS’ C API to other packages) and MUMPS from the rmumps dependency, so there is no separate HiGHS or MUMPS installation and nothing of either is compiled here. A source build binds to the rmumps installed at the time: rmumps 5.2.1-44 or later through its versioned C interface (rmumps 5.9.1-1 brings MUMPS 5.9.1), rmumps 5.2.1-43 through the legacy dmumps_c entry point.

Quick example

Hock–Schittkowski problem 15 (x* = (0.5, 2), f* = 306.5), solved with the interior-point preset. Derivatives are supplied in COO form (0-based indices); the Hessian is the lower triangle of the Lagrangian.

library(Uno)

objective   <- function(x) 100 * (x[2] - x[1]^2)^2 + (1 - x[1])^2
gradient    <- function(x) c(400 * x[1]^3 - 400 * x[1] * x[2] + 2 * x[1] - 2,
                             200 * (x[2] - x[1]^2))
constraints <- function(x) c(x[1] * x[2], x[1] + x[2]^2)
jacobian    <- function(x) c(x[2], 1, x[1], 2 * x[2])
hessian     <- function(x, sigma, lambda)
  c(sigma * (1200 * x[1]^2 - 400 * x[2] + 2),
    -400 * sigma * x[1] - lambda[1],
    200 * sigma - 2 * lambda[2])

res <- uno_solve(
  n = 2L, lb = c(-Inf, -Inf), ub = c(0.5, Inf), sense = "minimize",
  obj = objective, grad = gradient,
  m = 2L, cl = c(1, 0), cu = c(Inf, Inf), cons = constraints,
  jac_rows = c(0L, 1L, 0L, 1L), jac_cols = c(0L, 0L, 1L, 1L), jac = jacobian,
  hess_rows = c(0L, 1L, 1L), hess_cols = c(0L, 0L, 1L), hess = hessian,
  x0 = c(-2, 1), preset = "ipopt", base_indexing = 0L, verbose = FALSE,
  options = list(logger = "SILENT")
)

res$objective   # 306.5
res$primal      # 0.5 2

Any Uno solver option can be passed through options as a named list (applied after the preset). See vignette("Uno") for the full walk-through.

Citation

To cite the R package, run citation("Uno"), or:

Narasimhan B (2026). Uno: R Interface to the Uno Nonlinear Optimization Solver. R package. https://github.com/bnaras/Uno.

To cite the Uno solver itself, use the references its authors maintain under “Cite Uno”: the theory paper (Vanaret and Leyffer, 2026, Mathematical Programming Computation, https://doi.org/10.1007/s12532-026-00310-9) and the software paper (Vanaret and Montoison, 2026, Journal of Open Source Software, https://doi.org/10.21105/joss.10229).

License

MIT. The bundled Uno solver is Copyright Charlie Vanaret and contributors, also MIT; see inst/COPYRIGHTS for every copyright holder of bundled code. HiGHS and MUMPS are not bundled; they come from the highs and rmumps packages.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.