SpatEntropy (version 0.1.0)

couple_count: Build ordered couples in a dataset.

Description

This function builds and counts the number of all types of ordered couples in a data vector or matrix, according to a chosen adjacency matrix. 'Ordered' means that a couple (i,j) is different than a couple (j,i).

Usage

couple_count(data, adj.mat, missing.cat = NULL)

Arguments

data

A matrix or vector, can be numeric, factor, character... If the dataset is a point pattern, data is the mark vector.

adj.mat

An adjacency matrix, upper- or lower-triangular. Provided by user or generated by adj_mat.

missing.cat

A vector with the names of all categories that are absent in data.

Value

The number of couples, and a table with absolute and relative frequencies for each couple of categories.

Details

This function needs a data matrix or data vector of any type (numeric, factor, character, ...), and an adjacency matrix as generated by adj_mat(). It returns all the data couples identified by the adjacency matrix, i.e. occurring at the chosen neighbourhood distance. Relative and absolute frequencies for all possible couples are returned, and may be used for computation of spatial entropy at the chosen distance range. 'Ordered' means that the relative spatial location is relevant, i.e. that a couple where category \(i\) occurs at the left of category \(j\) is different from a couple where category \(j\) occurs at the left of category \(i\).

Examples

# NOT RUN {
dist.mat=euclid_dist(cbind(rep(1:5, each=5), rep(1:5,5)))
adj.mat=adj_mat(dist.mat, dd1=dist.mat[1,2]) #for the contiguity matrix
couple_count(sample(1:3, 25, replace=TRUE), adj.mat)

# }