Provides tools for systematically exploring large quantities of 
             temporal data across cyclic temporal granularities
             (deconstructions of time) by visualizing probability distributions.
             Cyclic time granularities can be circular, quasi-circular or 
             aperiodic. 'gravitas' computes cyclic
             single-order-up or multiple-order-up granularities, check the
             feasibility of creating plots for any two cyclic granularities
             and recommend probability distributions plots for exploring
             periodicity in the data.

A wrapper of different standard estimation methods for gravity models. 
  This package provides estimation methods for log-log models and multiplicative models.

Implements a one-sector Armington-CES gravity model with general equilibrium (GE) effects. This model is designed to analyze international and domestic trade by capturing the impacts of trade costs and policy changes within a general equilibrium framework. Additionally, it includes a local parameter to run simulations on productivity. The package provides functions for calibration, simulation, and analysis of the model.

Computes the gravitational and magnetic anomalies generated by
  3-D vertical rectangular prisms at specific observation points using the
  method of Plouff (1976) <doi:10.1190/1.1440645>.

The 'gRbase' package provides graphical modelling features
    used by e.g. the packages 'gRain', 'gRim' and 'gRc'. 'gRbase' implements
    graph algorithms including (i) maximum cardinality search (for marked
    and unmarked graphs).
    (ii) moralization, (iii) triangulation, (iv) creation of junction tree.
    'gRbase' facilitates array operations,
    'gRbase' implements functions for testing for conditional independence.
    'gRbase' illustrates how hierarchical log-linear models may be
    implemented and describes concept of graphical meta
    data. 
    The facilities of the package are documented in the book by Højsgaard,
    Edwards and Lauritzen (2012,
    <doi:10.1007/978-1-4614-2299-0>) and in the paper by 
    Dethlefsen and Højsgaard, (2005, <doi:10.18637/jss.v014.i17>).
    Please see 'citation("gRbase")' for citation details.