Builds and optimizes Hopfield artificial neural networks (Hopfield, 1982, <doi:10.1073/pnas.79.8.2554>). One-layer and three-layer models are implemented. The energy of the Hopfield network is minimized with formula from Krotov and Hopfield (2016, <doi:10.48550/ARXIV.1606.01164>). Optimization (supervised learning) is done through a gradient-based method. Classification is done with S3 methods predict(). Parallelization with 'OpenMP' is used if available during compilation.

The haversine is a function used to calculate the distance between a pair of 
    latitude and longitude points while accounting for the assumption that the points 
    are on a spherical globe. This package provides a fast, dataframe compatible, 
    haversine function. For the first publication on the haversine calculation see 
    Joseph de Mendoza y Ríos (1795) <https://books.google.cat/books?id=030t0OqlX2AC> (In Spanish).

A simple and time saving multiple linear regression function (OLS) with interpretation, optional bootstrapping, effect size calculation and all tested requirements.

Convert Chinese characters into Hanyu Pinyin (the official 
    romanization system for Standard Chinese) with support for tones, 
    toneless output, initials, URL slugs, and valid R variable names. 
    The package was inspired by the now-orphaned CRAN package 'pinyin' 
    (archived in April 2026 after the maintainer became unreachable). 
    'hanyupinyin' is a ground-up rewrite using the authoritative Unicode 
    Unihan database, a vectorized engine, and modern R practices. 
    Dictionary data are derived from the Unicode Unihan Database 
    (Unicode Consortium, 2025) <https://www.unicode.org/reports/tr38/>.

The following R functions are used for inference of trait
        associations with haplotypes and other covariates in
        generalized linear models.  The functions are developed
        primarily for data collected in cohort or cross-sectional
        studies. They can accommodate uncertain haplotype phase and
        handle missing genotypes at some SNPs.