Distance Variance Score: An Efficient Feature Selection Method in Text Classification

Algorithm 1

Algorithm of feature selection using DVS.

Procedure  

begin

 let   denotes the map storing and () and

 # is the matrix to store value of city block distance among documents and

 #

 #when ,

 for each in   do

  for each in   do

   ;

  end

 end

 #calculate for each

 for   in   do

  ;

  ;

 end

 #sort in decreasing order according to value

 ;

 #select and return the first features

 return  ;

end

Procedure  

# is the matrix to store value of city block distance among documents and

#

#when ,

begin

 let   denotes the standard variance of

 let   denotes feature distance contributions of

 let   denotes the index vector of samples in and

 #calculate .  See Section 3.1

 for each in   do

  for each in and   do

   #calculate city block distance between and . See Section 3.1

   ;

   #calculate city block distance between and . See Section 3.1

   ;

    += ;

  end

 end

 return  ;

end