Xi {discretization} | R Documentation |
This function is the \xi
, required to perform the Extended Chi2 discretization algorithm.
Xi(data)
data |
data matrix |
The following equality is used for calculating the least upper bound(\xi
) of the data set(Chao and Jyh-Hwa (2005)).
\xi(C,D) = max(m_1, m_2)
where
C
is the equivalence relation set,
D
is the decision set, and
C^{*}=\{E_1, E_2, \ldots, E_n \}
is the equivalence classes.
m_1 = 1- min\{c(E, D) | E \in C^*
and 0.5 < c(E,D) \}
,
m_2 = 1- max\{c(E, D) | E \in C^*
and c(E,D) < 0.5\}
.
c(E, D) = 1- \frac{card(E \cap D)}{card(E)}
card
denotes set cardinality.
Xi |
numeric value, |
HyunJi Kim polaris7867@gmail.com
Chao-Ton, S. and Jyh-Hwa, H. (2005). An Extended Chi2 Algorithm for Discretization of Real Value Attributes, IEEE transactions on knowledge and data engineering, Vol. 17, No. 3, 437–441.
Ziarko, W. (1993). Variable Precision Rough Set Model, Journal of computer and system sciences, Vol. 46, No. 1, 39–59.