distchi2 {GeoXp}R Documentation

It gives an euclidian distance matrix for factors using metric of chi2.

Description

The function distchi2 calculates an euclidian distance matrix for factors using metric of chi^2.

Usage

distchi2(mat)

Arguments

mat A matrix of factors given as numeric values

Details

The euclidian distance between two individuals $i$ and $k$ using the metric of chi^2 is given by :

d^2_(chi^2)=n/p sum_j^p sum_l^m_j delta_ik^(jl) 1/n_l^j

with n, number of individuals, p number of variables, m_j is the number of possibilities for variable Y^j, n_l^j is the number of individuals where $l$ has been observed for Y^j and delta_ik^(jl)=1 if there is a discordance between $i$ and $k$ for $l$ and 0 otherwise. It is not an interactive function.

Value

It returns a dist object (see help(dist)).

Author(s)

Thibault LAURENT

References

Besse Philippe, Data mining 2 : Modélisation statistique et apprentissage.

See Also

clustermap


[Package GeoXp version 1.4 Index]