Efficient C++ optimized functions for numerical and symbolic calculus as described in Guidotti (2022) <doi:10.18637/jss.v104.i05>. It includes basic arithmetic, tensor calculus, Einstein summing convention, fast computation of the Levi-Civita symbol and generalized Kronecker delta, Taylor series expansion, multivariate Hermite polynomials, high-order derivatives, ordinary differential equations, differential operators (Gradient, Jacobian, Hessian, Divergence, Curl, Laplacian) and numerical integration in arbitrary orthogonal coordinate systems: cartesian, polar, spherical, cylindrical, parabolic or user defined by custom scale factors.

This is a one-function package that will pass only unique values to a computationally-expensive function that returns an output of the same length as the input.
    In importing and working with tidy data, it is common to have index columns, often including time stamps that are far from unique. Some functions to work with these such as text conversion to other variable types (e.g. as.POSIXct()), various grep()-based functions, and often the cut() function are relatively slow when working with tens of millions of rows or more.

Provides function to create, read, write, and work with
    'iCalendar' files (which typically have '.ics' or '.ical' extensions),
    and the scheduling data, calendars and timelines of people,
    organisations and other entities that they represent.  'iCalendar' is
    an open standard for exchanging calendar and scheduling information
    between users and computers, described at <https://icalendar.org/>.

Contains the function calendR() for creating fully customizable monthly and yearly calendars (colors, fonts, formats, ...) and even heatmap calendars. In addition, it allows saving the calendars in ready to print A4 format PDF files.

Fork of 'calendR' R package to generate ready to print
  calendars with 'ggplot2' (see <https://r-coder.com/calendar-plot-r/>)
  with additional features (backwards compatible).
  'calendRio' provides a 'calendR()' function that serves as a drop-in
  replacement for the upstream version but allows for additional
  parameters unlocking extra functionality.