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

function [xvalue,fa1]=fa(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; 
loglength=floor(log2(datalength))-1; 
 
for xlength=1:loglength 
    y1=dataset(1:datalength-2^xlength); 
    y2=dataset((1+2^xlength):datalength); 
    diff_y=(y2-y1).^2; 
    xvalue(xlength)=xlength; 
    fa_value(xlength)=sqrt(mean(diff_y)); 
end 
fa1=log2(fa_value); 
plot(xvalue,fa1);