datanormalize.m

这是一个支持向量机的工具

function [dc,md,mi]=datanormalize(da,choise,oldscale,oldmi)
% each column as an variable is normalized by its standard variance
% All rights Reserved, March 2006. Kaijun WANG

[nr,nc] = size(da);
if choise==1
 if oldscale(1) > 0
  mi=oldmi;
  md=oldscale;
 else
  mi=mean(da);
  md=std(da,0,1);          % caculate standard variance
  R=find(md==0);
  md(R)=mi(R);
 end
 da=da-repmat(mi,nr,1);
 dc=(da./repmat(md,nr,1)); % normalize each element
 
elseif choise==2
 % [-1,1] for each column
 if oldscale(1) >0
  md=oldscale;
  mi=oldmi;
 else
  Mi=max(da);
  mi=min(da);
  md=(Mi-mi)/2;
 end
  
 for i=1:nc
  dc(:,i)=(da(:,i)-mi(i))/md(i)-1;
 end
 
else
  dc=da;
  md=ones(1,nc);  
  mi=0;
end