Implements methods for functional data analysis based on the epigraph 
  and hypograph indices. These methods transform 
  functional datasets, whether in one or multiple dimensions, into multivariate 
  datasets. The transformation involves applying the epigraph, hypograph, and 
  their modified versions to both the original curves and their first and second 
  derivatives. The calculation of these indices is tailored to the dimensionality 
  of the functional dataset, with special considerations for dependencies between 
  dimensions in multidimensional cases. This approach extends traditional multivariate
  data analysis techniques to the functional data setting. A key application of 
  this package is the EHyClus method, which enhances clustering analysis for 
  functional data across one or multiple dimensions using the epigraph and 
  hypograph indices. See Pulido et al. (2023) <doi:10.1007/s11222-023-10213-7>
  and Pulido et al. (2024) <doi:10.48550/arXiv.2307.16720>.

Software accompanying Gary King's book: A Solution to the Ecological Inference Problem. (1997). Princeton University Press. ISBN 978-0691012407.

Provides more than 550 data sets of actual election results. 
    Each of the data sets includes aggregate party and candidate outcomes at the voting
    unit (polling stations) level and two-way cross-tabulated results at the district level.
    These data sets can be used to assess ecological inference algorithms devised 
    for estimating RxC (global) ecological contingency tables using exclusively aggregate results 
    from voting units.
    Reference:
    Pavía (2022) <doi:10.1177/08944393211040808>.

Provides API access to data from the U.S. Energy Information Administration ('EIA') <https://www.eia.gov/>.
    Use of the EIA's API and this package requires a free API key obtainable at <https://www.eia.gov/opendata/register.php>.
    This package includes functions for searching the EIA data directory and returning time series and geoset time series datasets.
    Datasets returned by these functions are provided by default in a tidy format, or alternatively, in more raw formats.
    It also offers helper functions for working with EIA date strings and time formats and for inspecting different summaries of series metadata.
    The package also provides control over API key storage and caching of API request results.