Functions to model and decompose time series into principal components using singular spectrum analysis (de Carvalho and Rua (2017) <doi:10.1016/j.ijforecast.2015.09.004>; de Carvalho et al (2012) <doi:10.1016/j.econlet.2011.09.007>).

Lightweight validation tool for checking function arguments and 
  validating data analysis scripts. This is an alternative to stopifnot() from 
  the 'base' package  and to assert_that() from the 'assertthat' package. It 
  provides more informative error messages and facilitates debugging.

Simple, flexible, assertions on data.frame or data.table objects with verbose output for vetting. While other assertion packages apply towards more general use-cases, assertable is tailored towards tabular data. It includes functions to check variable names and values, whether the dataset contains all combinations of a given set of unique identifiers, and whether it is a certain length. In addition, assertable includes utility functions to check the existence of target files and to efficiently import multiple tabular data files into one data.table.

Provides simple assertions with sensible defaults and customisable error messages. 
  It offers convenient assertion call wrappers and a general assert function that can handle any condition.
  Default error messages are user friendly and easily customized with inline code evaluation and styling powered by the 'cli' package.

Provides functionality to assert conditions
    that have to be met so that errors in data used in
    analysis pipelines can fail quickly. Similar to
    'stopifnot()' but more powerful, friendly, and easier
    for use in pipelines.

An extension to stopifnot() that makes it easy to declare 
    the pre and post conditions that you code should satisfy, while also 
    producing friendly error messages so that your users know what's gone
    wrong.

Provides assessment tools for regression models with discrete and semicontinuous outcomes proposed in Yang (2023) <doi:10.48550/arXiv.2308.15596>. It calculates the double probability integral transform (DPIT) residuals, constructs QQ plots of residuals and the ordered curve for assessing mean structures.