Bayesian Emulation of Computer Programs

Allows one to estimate the output of a computer program, as a function of the input parameters, without actually running it. The computer program is assumed to be a Gaussian process, whose parameters are estimated using Bayesian techniques that give a PDF of expected program output. This PDF is conditional on a training set of runs, each consisting of a point in parameter space and the model output at that point. The emphasis is on complex codes that take weeks or months to run, and that have a large number of undetermined input parameters; many climate prediction models fall into this class. The emulator essentially determines Bayesian posterior estimates of the PDF of the output of a model, conditioned on results from previous runs and a user-specified prior linear model. The package includes functionality to evaluate quadratic forms efficiently.

Methods for Changepoint Detection

Implements various mainstream and specialised changepoint methods for finding single and multiple changepoints within data. Many popular non-parametric and frequentist methods are included. The cpt.mean(), cpt.var(), cpt.meanvar() functions should be your first point of call.

Create and Explore Geographic Zoning Systems

Functions, documentation and example data to help divide geographic space into discrete polygons (zones). The package supports new zoning systems that are documented in the accompanying paper, "ClockBoard: A zoning system for urban analysis", by Lovelace et al. (2022) . The functions are motivated by research into the merits of different zoning systems (Openshaw, 1977) . A flexible ClockBoard zoning system is provided, which breaks-up space by concentric rings and radial lines emanating from a central point. By default, the diameter of the rings grow according to the triangular number sequence (Ross & Knott, 2019) with the first 4 doughnuts (or annuli) measuring 1, 3, 6, and 10 km wide. These annuli are subdivided into equal segments (12 by default), creating the visual impression of a dartboard. Zones are labelled according to distance to the centre and angular distance from North, creating a simple geographic zoning and labelling system useful for visualising geographic phenomena with a clearly demarcated central location such as cities.

Non-Ordered Vectors

Functionality for manipulating values of associative maps. The package is a dependency for mvp-type packages that use the STL map class: it traps plausible idiom that is ill-defined (implementation-specific) and returns an informative error, rather than returning a possibly incorrect result. To cite the package in publications please use Hankin (2022) .

Propensity to Cycle Tool

Functions and example data to teach and increase the reproducibility of the methods and code underlying the Propensity to Cycle Tool (PCT), a research project and web application hosted at < https://www.pct.bike/>. For an academic paper on the methods, see Lovelace et al (2017) .

Create, Read, Write, and Work with 'iCalendar' Files, Calendars and Scheduling Data

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/>.

Flexible Framework for Developing Spatial Interaction Models

Develop spatial interaction models (SIMs). SIMs predict the amount of interaction, for example number of trips per day, between geographic entities representing trip origins and destinations. Contains functions for creating origin-destination datasets from geographic input datasets and calculating movement between origin-destination pairs with constrained, production-constrained, and attraction-constrained models (Wilson 1979) .

Import 'OpenStreetMap' Data as Simple Features or Spatial Objects

Download and import of 'OpenStreetMap' ('OSM') data as 'sf' or 'sp' objects. 'OSM' data are extracted from the 'Overpass' web server (< https://overpass-api.de/>) and processed with very fast 'C++' routines for return to 'R'.

Octonions and Quaternions

Quaternions and Octonions are four- and eight- dimensional extensions of the complex numbers. They are normed division algebras over the real numbers and find applications in spatial rotations (quaternions), and string theory and relativity (octonions). The quaternions are noncommutative and the octonions nonassociative. See the package vignette for more details.

The Gauss Hypergeometric Function

The Gaussian hypergeometric function for complex numbers.