wolffd@0: function varargout = mirskewness(orig,varargin)
wolffd@0: %   s = skewness(x) calculates the skewness of x, showing the (lack of)
wolffd@0: %       symmetry of the curve.
wolffd@0: %   x can be either:
wolffd@0: %       - a spectrum (spectral skewness),
wolffd@0: %       - an envelope (temporal skewness), or
wolffd@0: %       - any histogram.
wolffd@0: 
wolffd@0: 
wolffd@0: varargout = mirfunction(@mirskewness,orig,varargin,nargout,struct,@init,@main);
wolffd@0: 
wolffd@0: 
wolffd@0: function [x type] = init(x,option)
wolffd@0: if not(isamir(x,'mirdata')) || isamir(x,'miraudio')
wolffd@0:     x = mirspectrum(x);
wolffd@0: end
wolffd@0: type = 'mirscalar';
wolffd@0: 
wolffd@0: 
wolffd@0: function s = main(x,option,postoption)
wolffd@0: if iscell(x)
wolffd@0:     x = x{1};
wolffd@0: end
wolffd@0: y = peaksegments(@skewness,get(x,'Data'),...
wolffd@0:                            get(x,'Pos'),...
wolffd@0:                            get(mircentroid(x),'Data'),...
wolffd@0:                            get(mirspread(x),'Data'));
wolffd@0: if isa(x,'mirspectrum')
wolffd@0:     t = 'Spectral skewness';
wolffd@0: elseif isa(x,'mirenvelope')
wolffd@0:     t = 'Temporal skewness';
wolffd@0: else
wolffd@0:     t = ['Skewness of ',get(x,'Title')];
wolffd@0: end
wolffd@0: s = mirscalar(x,'Data',y,'Title',t,'Unit','');
wolffd@0: 
wolffd@0: 
wolffd@0: function s = skewness(d,p,c,sp)
wolffd@0: s = sum((p-c).^3.*d) ./ sum(d) ./ sp.^3;