falpha.m

一个计算多重分形谱的matlab程序

function [f,alpha,dq,rq]=falpha(x,q,trace);
% from fdim.sh
% Estimates multi-fractal f(alpha) curve of a set of points x;
% produces a piecewise linear curve, the pieces depending upon q.
% v0.10  01/7/94, copyright AJ Roberts, [e-mail]
% Made publically available under the GNU arrangements.
%
% x(j,:) = coordinates of the jth point of a set
% trace  = optional argument: set to 1 if you want trace prints and graphics,
%          otherwise omit or set to 0
%
% The following may be changed to give better resolution
% q=[-8 -4 -2 -1 -0.5 0 0.5 1 2 4 8];
nalpha=40; 
%
if nargin<2, trace=0; end
[dq,rq]=fdim(q,x,trace); 
if trace, plot(q,dq,'g*'); title('interpolated Dq curve'); hold on; end;
while length(q)<nalpha,
   q=hint(q);
   dq=hint(dq);
end;
if trace, plot(q,dq); hold off; pause(5); end;
tau=(1-q).*dq;
alpha=-diff(tau)./diff(q);
amin=min(alpha);
amax=max(alpha);
alpha=amin+(0:nalpha)*(amax-amin)/nalpha;
f=min( tau'*ones(size(alpha))+q'*alpha );
alpha=alpha(f>0);
f=f(f>0);
if trace, 
   figure;plot(alpha,f); 
   axis([0 ceil(max(alpha)) 0 ceil(max(f))]);
   title('Multi-fractal  f(alpha) curve'); 
end;
% end;
% END_OF_FILE
% if test 1101 -ne `wc -c <'falpha.m'`; then
%     echo shar: \"'falpha.m'\" unpacked with wrong size!
% fi
% # end of 'falpha.m'
% fi
% if test -f 'fdim.m' -a "${1}" != "-c" ; then 
%   echo shar: Will not clobber existing file \"'fdim.m'\"
% else
% echo shar: Extracting \"'fdim.m'\" \(2107 characters\)
% sed "s/^X//" >'fdim.m' <<'END_OF_FILE'