sus

 [Index]=sus(SelCant,Sumvector) 
 sus:  Stocastic Universal Sampling method. Use as an alternative to
       roullete wheel selection to choose a sample of SelCant points according to a distribution for
       different type of samples
 INPUTS
 SelCant: Number of samples
 Sumvector: Cumulative distribution of an original distribution specifying
            the probability associated to each class.
 OUTPUTS
  Index:   Index(i) specifies to which class sample i belongs to, where
           the number of classes is size(Sumvector,2)

 EXAMPLE
         [Index]=sus(10,[0.8,1.0]): Choose 10 samples from two classes.
         The first with probability 0.8, the second with probability 0.2
 
 Last version 8/26/2008. Roberto Santana (roberto.santana@ehu.es)

0001 function[Index]=sus(SelCant,Sumvector) 
0002 % [Index]=sus(SelCant,Sumvector)
0003 % sus:  Stocastic Universal Sampling method. Use as an alternative to
0004 %       roullete wheel selection to choose a sample of SelCant points according to a distribution for
0005 %       different type of samples
0006 % INPUTS
0007 % SelCant: Number of samples
0008 % Sumvector: Cumulative distribution of an original distribution specifying
0009 %            the probability associated to each class.
0010 % OUTPUTS
0011 %  Index:   Index(i) specifies to which class sample i belongs to, where
0012 %           the number of classes is size(Sumvector,2)
0013 %
0014 % EXAMPLE
0015 %         [Index]=sus(10,[0.8,1.0]): Choose 10 samples from two classes.
0016 %         The first with probability 0.8, the second with probability 0.2
0017 %
0018 % Last version 8/26/2008. Roberto Santana (roberto.santana@ehu.es)
0019 
0020 aux=rand(1,1);
0021 
0022 toadd=1/SelCant;
0023 
0024 cant=1;
0025 
0026 while cant<=SelCant
0027  count=1;
0028   while aux>Sumvector(count) 
0029    count=count+1;
0030   end
0031   Index(cant)=count;
0032   cant=cant+1;
0033   aux=aux+toadd;
0034   if aux>1
0035    aux=aux-1;
0036   end
0037 end
0038 
0039 torandomize = randperm(SelCant);
0040 Index = Index(torandomize);
0041 return
0042