www.pudn.com > DFA_and_FA.rar > dfa.m

function [xvalue,fa1]=dfa(data); 
mean_data=data-mean(data); 
datalength=length(mean_data); 
%  for sumlength=1:datalength 
%     dataset(sumlength)=sum(mean_data(1:sumlength)); 
%  end 
dataset=mean_data; 
dataset=dataset.^2; 
loglength=floor(log2(datalength)); 
for xlength=1:loglength 
    segnum=2^(loglength/xlength); 
    for segvalue=1:segnum 
        m=(1+(segvalue-1)*xlength):(segvalue*xlength); 
        y1(segvalue)=sum(dataset(m)); 
    end 
     fa_value(xlength)=sqrt(mean(y1)); 
     clear y1; 
     xvalue(xlength)=xlength; 
end 
fa1=log2(fa_value); 
plot(xvalue,fa1);