Impurity Function
Equations
Gini Impurity
H ( X m ) = ∑ k p m k ( 1 − p m k )
Information Entropy
H ( X m ) = − ∑ k p m k log ( p m k )
Mean Square Error
H ( X m ) = 1 N m ∑ i ∈ N m ( y − y ¯ m ) 2
Absolute Mean Error