# bayesianOverlap: Calculate the overlap between two ellipses based on their... In SIBER: Stable Isotope Bayesian Ellipses in R

## Description

This function loops over the posterior distribution of the means and covariances matrices of two specified groups.

## Usage

 ```1 2 3 4 5 6 7 8 9``` ```bayesianOverlap( ellipse1, ellipse2, ellipses.posterior, draws = 10, p.interval = 0.95, n = 100, do.plot = FALSE ) ```

## Arguments

 `ellipse1` character code of the form `"x.y"` where `x` is an integer indexing the community, and `y` an integer indexing the group within that community. This specifies the first of two ellipses whose overlap will be compared. `ellipse2` same as `ellipse1` specifying a second ellipse. `ellipses.posterior` a list of posterior means and covariances fitted using `siberEllipses`. `draws` an integer specifying how many of the posterior draws are to be used to estimate the posterior overlap. Defaults to `10` which uses the first 10 draws. In all cases, the selection will be `1:draws` so independence of the posterior draws is assumed. Setting to `NULL` will use all the draws (WARNING - like to be very slow). `p.interval` the prediction interval used to scale the ellipse as per `addEllipse`. `n` the number of points on the edge of the ellipse used to define it. Defaults to `100` as per `addEllipse`. `do.plot` logical switch to determine whether the corresponding ellipses should be plotted or not. A use-case would be in conjunction with a low numbered `draws` so as to visualise a relatively small number of the posterior ellipses. Defaults to `FALSE`.

## Value

A data.frame comprising three columns: the area of overlap, the area of the first ellipse and the area of the second ellipse and as many rows as specified by `draws`.

SIBER documentation built on April 13, 2021, 5:07 p.m.