Changes in version 2025-10-13                      

Added

  - Ranger backend (default): missForest() can now fit forests via
    ranger with backend = "ranger" (default) or retain legacy behavior
    with backend = "randomForest".
  - Backend selector: New argument backend = c("ranger",
    "randomForest").
  - Threading control: New argument num.threads (used by ranger). In
    parallelize = "variables" mode, per-variable ranger calls use
    num.threads = 1 to avoid oversubscription.

Changed

  - Argument mapping for ranger:
      - ntree → num.trees
      - nodesize = c(num, fac) → min.bucket (regression/classification
        respectively)
      - sampsize (counts) → sample.fraction (overall or per-class
        fractions)
      - classwt → class.weights
      - cutoff emulated via probability forests + post-thresholding
      - maxnodes has no exact equivalent and is ignored by ranger
        (consider max.depth at the ranger level if needed).
  - Defaults for node size: nodesize = c(5, 1) interpreted consistently
    across backends (numeric first, factor second).
  - Parallelization behavior clarified:
      - parallelize = "variables": builds per-variable forests in
        parallel via foreach; ranger runs with num.threads = 1 inside
        each task.
      - parallelize = "forests": uses ranger’s internal threading (via
        num.threads) or combines sub-forests for randomForest.

Fixed

  - Prevented name conflicts and S3 confusion by narrowing imports
    (e.g., stats::predict) and explicitly importing only what’s used.
  - Resolved NOTE about undefined xntree in foreach by
    localizing/binding the chunk variable in the loop.
  - Corrected usage of iterator utilities by importing
    itertools::isplitVector and iterators::idiv.
  - Removed unused macro imports and unicode arrows in Rd files that
    triggered warnings.

Documentation

  - Help pages refreshed with backend details, parameter mappings, and
    clear parallelization guidance.
  - Cross-references now use package-qualified links:
      - \link[randomForest]{randomForest} and \link[ranger]{ranger}.
  - Examples modernized (showing both backends and optional parallel
    usage).
  - CITATION modernized to bibentry() with person()/c() and DOI.
  - README rewritten to clearly explain capabilities, backends, and
    typical usage patterns.

Internal / Packaging

  - DESCRIPTION
      - Version: 1.6 and current Date.
      - Added Authors@R.
      - Updated Imports to include only used packages (e.g., ranger,
        randomForest, foreach, iterators, itertools, doRNG, stats).
  - NAMESPACE
      - Explicit, minimal imports to avoid clashes and CRAN checks.
      - Exported only user-facing functions: missForest, mixError,
        nrmse, prodNA, varClass.

Compatibility Notes

  - Results across backends should be similar but not identical due to
    implementation differences (sampling semantics, splits, probability
    handling).
  - maxnodes is ignored with backend = "ranger"; consider max.depth at
    the ranger level if tree depth control is required.

                 Changes in version 1.6.1 (2025-10-26)                  

Fixes and robustness improvements

  - Fixed a parallelization edge case in parallelize = "variables" mode
    where empty index chunks could lead to uninitialized results.

  - Added defensive guards (tryCatch, zero-length handling) to prevent
    “object 'results' not found” errors during variable-level parallel
    imputation.

  - Improved handling of edge cases with few or single predictors
    (zero-covariate fallback).

  - Introduced automatic worker capping to prevent errors when the
    number of parallel cores exceeds the number of variables.

  - Enhanced internal stability for both ranger and randomForest
    backends in low-dimensional or degenerate datasets.

  - Expanded the internal test suite with ADAPTS-like stress tests
    covering:
    
      - mixed-type small datasets
      - single-column and zero-covariate cases
      - both parallelization modes and backends