Classes (S4) of commonly used elliptical, Archimedean,
 extreme-value and other copula families, as well as their rotations,
 mixtures and asymmetrizations. Nested Archimedean copulas, related
 tools and special functions. Methods for density, distribution, random
 number generation, bivariate dependence measures, Rosenblatt transform,
 Kendall distribution function, perspective and contour plots. Fitting of
 copula models with potentially partly fixed parameters, including
 standard errors. Serial independence tests, copula specification tests
 (independence, exchangeability, radial symmetry, extreme-value
 dependence, goodness-of-fit) and model selection based on
 cross-validation. Empirical copula, smoothed versions, and
 non-parametric estimators of the Pickands dependence function.

Additive copula regression for regression
    problems with binary outcome via gradient boosting 
    [Brant, Hobæk Haff (2022); <arXiv:2208.04669>]. The fitting process
    includes a specialised model selection algorithm for each component, where
    each component is found (by greedy optimisation) among all the D-vines with
    only Gaussian pair-copulas of a fixed dimension, as specified by the user.
    When the variables and structure have been selected, the algorithm then
    re-fits the component where the pair-copula distributions can be different
    from Gaussian, if specified.

Copula-based regression models for multivariate censored data, including 
 bivariate right-censored data, bivariate interval-censored data, and right/interval-censored 
 semi-competing risks data. Currently supports Clayton, Gumbel, Frank, Joe, AMH and 
 Copula2 copula models. For marginal models, it supports parametric (Weibull, Loglogistic, 
 Gompertz) and semiparametric (Cox and transformation) models. Includes methods for 
 convenient prediction and plotting. Also provides a bivariate time-to-event simulation 
 function and an information ratio-based goodness-of-fit test for copula. Method details 
 can be found in Sun et.al (2019) Lifetime Data Analysis, Sun et.al (2021) Biostatistics, 
 Sun et.al (2022) Statistical Methods in Medical Research, Sun et.al (2022) Biometrics, and
 Sun et al. (2023+) JRSSC.