119 lines
3.0 KiB
Mathematica
119 lines
3.0 KiB
Mathematica
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function [ext, exttime] = sig2ext(sig, dt, clsn)
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% SIG2EXT - search for local extrema in the time history (signal),
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%
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% function [ext, exttime] = sig2ext(sig, dt, clsn)
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%
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% SYNTAX
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% sig2ext(sig)
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% [ext]=sig2ext(sig)
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% [ext,exttime]=sig2ext(sig)
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% [ext,exttime]=sig2ext(sig, dt)
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% [ext,exttime]=sig2ext(sig, dt, clsn)
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%
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% OUTPUT
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% EXT - found extrema (turning points of the min and max type)
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% in time history SIG,
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% EXTTIME - option, time of extremum occurrence counted from
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% sampling time DT (in seconds) or time vector DT.
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% If no sampling time present, DT = 1 is assumed.
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%
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% INPUT
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% SIG - required, time history of loading,
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% DT - option, descripion as above, scalar or vector of
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% the same length as SIG,
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% CLSN - option, a number of classes of SIG (division is performed
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% before searching of extrema), no CLSN means no division
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% into classes.
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%
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% The function caused without an output draws a course graph with
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% the searched extrema.
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%
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% By Adam Nies<EFBFBD>ony
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% Revised, 10-Nov-2009
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% Visit the MATLAB Central File Exchange for latest version
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error(nargchk(1,3,nargin))
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% Is the time analysed?
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TimeAnalize=(nargout==0)|(nargout==2);
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% Sprawdzam czy przyrost dt jest podany prawid<EFBFBD>owo
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if nargin==1,
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dt=1;
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else
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dt=dt(:);
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end
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% Zamieniam dane sig na jedn<EFBFBD> kolumn<EFBFBD>
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sig=sig(:);
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% Dzielimy na klasy je<EFBFBD>eli jest podane CLSN
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if nargin==3,
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if nargout==0,
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oldsig=sig;
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end
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clsn=round(clsn);
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smax=max(sig);
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smin=min(sig);
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sig=clsn*((sig-smin)./(smax-smin));
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sig=fix(sig);
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sig(sig==clsn)=clsn-1;
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sig=(smax-smin)/(clsn-1)*sig+smin;
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end
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% Tworz<EFBFBD> wektor binarny w gdzie 1 oznacza ekstremum lub r<EFBFBD>wno<EFBFBD><EFBFBD>,
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% Uznaj<EFBFBD> <EFBFBD>e pierwszy i ostatni punkt to ekstremum
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w1=diff(sig);
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w=logical([1;(w1(1:end-1).*w1(2:end))<=0;1]);
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ext=sig(w);
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if TimeAnalize,
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if length(dt)==1,
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exttime=(find(w==1)-1).*dt;
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else
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exttime=dt(w);
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end
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end
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% Usuwam potr<EFBFBD>jne warto<EFBFBD>ci
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w1=diff(ext);
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w=~logical([0; w1(1:end-1)==0 & w1(2:end)==0; 0]);
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ext=ext(w);
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if TimeAnalize,
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exttime=exttime(w);
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end
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% Usuwam podw<EFBFBD>jne warto<EFBFBD>ci i przesuwam czas na <EFBFBD>rodek
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w=~logical([0; ext(1:end-1)==ext(2:end)]);
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ext=ext(w);
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if TimeAnalize,
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w1=(exttime(2:end)-exttime(1:end-1))./2;
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exttime=[exttime(1:end-1)+w1.*~w(2:end); exttime(end)];
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exttime=exttime(w);
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end
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% Jeszcze raz sprawdzam ekstrema
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if length(ext)>2, % warunek: w tym momencie mo<EFBFBD>e ju<EFBFBD> by<EFBFBD> ma<EFBFBD>o punkt<EFBFBD>w
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w1=diff(ext);
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w=logical([1; w1(1:end-1).*w1(2:end)<0; 1]);
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ext=ext(w);
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if TimeAnalize,
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exttime=exttime(w);
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end
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end
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if nargout==0,
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if length(dt)==1,
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dt=(0:length(sig)-1).*dt;
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end
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if nargin==3,
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plot(dt,oldsig,'b-',dt,sig,'g-',exttime,ext,'ro')
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legend('signal','singal divided in classes','extrema')
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else
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plot(dt,sig,'b-',exttime,ext,'ro')
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legend('signal','extrema')
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end
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xlabel('time')
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ylabel('signal & extrema')
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clear ext exttime
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end
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