Rashomon Set of Optimal Trees R package ROOT version 0.2.0 Implements a general framework for globally optimizing user-specified objective functionals over interpretable binary weight functions represented as sparse decision trees, called ROOT (Rashomon Set of Optimal Trees). It searches over candidate trees to construct a Rashomon set of near-optimal solutions and derives a summary tree highlighting stable patterns in the optimized weights. ROOT includes a built-in generalizability mode for identifying subgroups in trial settings for transportability analyses (Parikh et al. (2025) <doi:10.1080/01621459.2025.2495319>). Software Depends: R (>= 3.5) Imports: MASS, rpart, gbm, stats, withr, rpart.plot Suggests: mlbench, testthat (>= 3.0.0), knitr, rmarkdown, ragg Peter Liu <bliu68@jh.edu> Comprehensive R Archive Network (CRAN) Yiren Hou [aut] (ORCID: <https://orcid.org/0009-0005-0422-4268>, Equal contribution), Peter Liu [aut, cre] (ORCID: <https://orcid.org/0009-0000-2691-5637>, Equal contribution), Sean McGrath [aut] (ORCID: <https://orcid.org/0000-0002-7281-3516>), Harsh Parikh [aut] (ORCID: <https://orcid.org/0000-0003-1927-8646>) MIT + file LICENSE (https://CRAN.R-project.org/package=ROOT/LICENSE) 2026-07-31 application/tgz https://CRAN.R-project.org/package=ROOT doi:10.32614/CRAN.package.ROOT