MuViCP (version 1.3.2)

ab.dist: Distance Functions for nearest neighbours

Description

These functions compute Absolute (ab.dist), Euclidean (eu.dist) or Mahalanobis (mh.dist) distances between two points. The variant functions (*.matY), accomplish the same task, but between a point on the one hand, and every point specified as rows of a matrix on the other.

Usage

ab.dist(x, y)
eu.dist(x, y)
mh.dist(x, y, A)
ab.dist.matY(x, Y)
eu.dist.matY(x, Y)
mh.dist.matY(x, Y, A)

Arguments

x

The vector (point) from which distance is sought.

y

The vector (point) to which distance is sought.

Y

A set of points, specified as rows of a matrix, to which distances are sought.

A

The inverse matrix to use for the Mahalanobis distance.

Value

corresponding to each row of Y.

Details

These functions are used internally to decide how the nearest neighbours shall be calculated; the user need not call any of these functions directly. Rather, the choice of distance is specified as a string ('euclidean' or 'absolute' or 'mahal').

See Also

get.NN

Examples

x <- c(1,2)
y <- c(0,3)
mu <- c(1,3)
Sigma <- rbind(c(1,0.2),c(0.2,1))
Y <- MASS::mvrnorm(20, mu = mu, Sigma = Sigma)
ab.dist(x,y)
eu.dist(x,y)
mh.dist(x,y,Sigma)
ab.dist.matY(x,Y)
eu.dist.matY(x,Y)
mh.dist.matY(x,Y,Sigma)