complexity.m

来自「有用的几个动力学物理量。包括自相关函数(acorr.m)」· M 代码 · 共 38 行

function cmp=complexity(x,n);
% cmp = complexity(x,n);
%
% calculate the Lempel-Ziv complexity of the n-bit encoding of x. 
%
% cmp is the normalised complexity, that is the number of distinct
% symbol sequences in x, divided by the expected number of distinct 
% symbols for a noise sequence.
%
% Algorithm is implemented in complexitybs.c
%
% M. Small
% [e-mail]
% 7/10/04

if nargin<2,
    n=2;
end;

if length(n)>1,
   for ni=1:length(n),
        cmp(ni)=complexity(x,n(ni)); 
   end;    
else,

    %do the binning, with equi-probably bins
    x=x(:);
    nx=length(x);
    [xn,xi]=sort(x);
    y=zeros(nx,1);
    y=1:nx;
    y=floor(y.*(n/(nx+1)));
    x(xi)=y;

    %compute complexity with complexitybs
    cmp=complexitybs(x+eps);

end;