scale_range.m

数据挖掘的工具箱,最新版的,希望对做这方面研究的人有用

%SCALE_RANGE Give a vector of scales
%
%     SIG = SCALE_RANGE(X,NR)
%
% Give a reasonable range of scales SIG for the dataset X. The largest
% scale is given first. If NR is given, the number of scales is NR.
% This function is useful in consistent_occ.
%
% Default: NR = 20
%
% See also: consistent_occ, parzen_dd, svdd

% Copyright: D. Tax, R.P.W. Duin, [e-mail]
% Faculty of Applied Physics, Delft University of Technology
% P.O. Box 5046, 2600 GA Delft, The Netherlands
  
function sig = scale_range(x,nr)

if nargin<2
	nr = 20;
end
if isdataset(x)
	x = +x;
end

% Compute the distances
d = sqrt(sqeucldistm(x,x));

% Find the largest and the smallest distance:
dmax = max(d(:));
d(d<=1e-12) = dmax;
dmin = min(d(:));

% ... and compute the range:
log10 = log(10);
sig = logspace(log(dmax)/log10,log(dmin)/log10,nr);

return