Adaptive Regularization using Cubics for Optimization R package arcopt version 0.3.0 Implements cubic regularization methods (ARC) for local optimization problems common in statistics and applied research. Provides robust handling of ill-conditioned, nonconvex, and indefinite Hessian problems with automatic saddle point escape. Supports box constraints; linear equality constraints are planned for a future release. Software Depends: R (>= 4.1.0) Imports: Rcpp (>= 1.0.0), utils LinkingTo: Rcpp Suggests: testthat (>= 3.0.0), knitr, rmarkdown, covr, marqLevAlg, trust Marcus Waldman <marcus.waldman@cuanschutz.edu> Comprehensive R Archive Network (CRAN) Marcus Waldman [aut, cre] MIT + file LICENSE (https://CRAN.R-project.org/package=arcopt/LICENSE) 2026-04-29 application/tgz https://CRAN.R-project.org/package=arcopt doi:10.32614/CRAN.package.arcopt