Changes in version 0.2.0                        

New features

  - Added positivity_trim argument to ROOT() and
    characterizing_underrep() for pre-trimming target observations with
    structural positivity violations prior to optimization. Supports a
    fixed numeric threshold (e.g., positivity_trim = 0.05) or the
    data-driven rule of Crump, Hotz, Imbens & Mitnik (2009, Biometrika)
    via positivity_trim = "crump". Only active in generalizability mode.
    Trimming metadata is stored in the returned object as
    positivity_trim_info and reported by summary().
  - Added split_strategy argument to ROOT() and
    characterizing_underrep() with options "midpoint" (default,
    backward-compatible) and "random_quantile". The random quantile
    strategy draws a uniform random quantile within quantile_range
    (default 10th–90th percentile) at each split, improving
    covariate-space coverage across the forest. The strategy used is
    stored in the returned object and reported by summary().
  - New internal helpers: crump_alpha(), trim_positivity_violations(),
    and split_point().

Documentation

  - Added roxygen documentation for all new arguments and helper
    functions.
  - Added Crump et al. (2009) to @references in ROOT().
  - summary.ROOT() now reports the split strategy and positivity
    trimming diagnostics.

Testing

  - New test files: test-positivity.R and test-split-strategy.R.

                 Changes in version 0.1.1 (2026-03-10)                  

  - Updated help files
  - Expanded unit testing
  - Updated authorship

                        Changes in version 0.1.0                        

  - First version released on GitHub
    (https://github.com/peterliu599/ROOT)