function [XSelected,XRest,vSelectedRowIndex]=ks(X,Num)
% ks selects the samples XSelected which uniformly distributed in the exprimental data X's space
% Input
% X:the matrix of the sample spectra
% Num:the number of the sample spectra you want select
% Output
% XSelected:the sample spectras was selected from the X
% XRest:the sample spectras remain int the X after select
% vSelectedRowIndex:the row index of the selected sample in the X matrix
% Programmer: zhimin zhang @ central south university on oct 28 ,2007
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% start of the kennard-stone step one
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[nRow,nCol]=size(X); % obtain the size of the X matrix
mDistance=zeros(nRow,nRow); %dim a matrix for the distance storage
vAllofSample=1:nRow;
for i=1:nRow-1
vRowX=X(i,:); % obtain a row of X
for j=i+1:nRow
vRowX1=X(j,:); % obtain another row of X
mDistance(i,j)=norm(vRowX-vRowX1); % calc the Euclidian distance
end
end
[vMax,vIndexOfmDistance]=max(mDistance);
[nMax,nIndexofvMax]=max(vMax);
%vIndexOfmDistance(1,nIndexofvMax)
%nIndexofvMax
vSelectedSample(1)=nIndexofvMax;
vSelectedSample(2)=vIndexOfmDistance(nIndexofvMax);
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% end of the kennard-stone step one
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% start of the kennard-stone step two
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for i=3:Num
vNotSelectedSample=setdiff(vAllofSample,vSelectedSample);
vMinDistance=zeros(1,nRow-i + 1);
for j=1:(nRow-i+1)
nIndexofNotSelected=vNotSelectedSample(j);
vDistanceNew = zeros(1,i-1);
for k=1:(i-1)
nIndexofSelected=vSelectedSample(k);
if(nIndexofSelected<=nIndexofNotSelected)
vDistanceNew(k)=mDistance(nIndexofSelected,nIndexofNotSelected);
else
vDistanceNew(k)=mDistance(nIndexofNotSelected,nIndexofSelected);
end
end
vMinDistance(j)=min(vDistanceNew);
end
[nUseless,nIndexofvMinDistance]=max(vMinDistance);
vSelectedSample(i)=vNotSelectedSample(nIndexofvMinDistance);
end
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%%%%% end of the kennard-stone step two
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%%%%% start of export the result
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vSelectedRowIndex=vSelectedSample;
for i=1:length(vSelectedSample)
XSelected(i,:)=X(vSelectedSample(i),:);
end
vNotSelectedSample=setdiff(vAllofSample,vSelectedSample);
for i=1:length(vNotSelectedSample)
XRest(i,:)=X(vNotSelectedSample(i),:);
end
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%%%%% end of export the result
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--
