What sig2ext in Matlab? - matlab

Question

What is sig2ext.m file in Matlab? If I want to use the function, should I install any specific toolbox.
Basically, I am trying to do a rainflow counting.

Answer 1

It looks like the function is part of this package:
https://mathworks.com/matlabcentral/fileexchange/3026-rainflow-counting-algorithm?focused=5148893&tab=function
If you want to use that function, all you have to do is to download the package, change your current Matlab working directory to the folder in which you unzipped the package, and create a new script in which you invoke it.
Alternatively, you can just copy and paste the function code into a new script file you previouslty created:
function [ext, exttime] = sig2ext(sig, dt, clsn)
% SIG2EXT - search for local extrema in the time history (signal),
%
% function [ext, exttime] = sig2ext(sig, dt, clsn)
%
% SYNTAX
% sig2ext(sig)
% [ext]=sig2ext(sig)
% [ext,exttime]=sig2ext(sig)
% [ext,exttime]=sig2ext(sig, dt)
% [ext,exttime]=sig2ext(sig, dt, clsn)
%
% OUTPUT
% EXT - found extrema (turning points of the min and max type)
% in time history SIG,
% EXTTIME - option, time of extremum occurrence counted from
% sampling time DT (in seconds) or time vector DT.
% If no sampling time present, DT = 1 is assumed.
%
% INPUT
% SIG - required, time history of loading,
% DT - option, descripion as above, scalar or vector of
% the same length as SIG,
% CLSN - option, a number of classes of SIG (division is performed
% before searching of extrema), no CLSN means no division
% into classes.
%
% The function caused without an output draws a course graph with
% the searched extrema.
%
% By Adam Niesony
% Revised, 10-Nov-2009
% Visit the MATLAB Central File Exchange for latest version
error(nargchk(1,3,nargin))
% Is the time analysed?
TimeAnalize=(nargout==0)|(nargout==2);
% Sprawdzam czy przyrost dt jest podany prawidowo
if nargin==1,
dt=1;
else
dt=dt(:);
end
% Zamieniam dane sig na jedn kolumn
sig=sig(:);
% Dzielimy na klasy jeeli jest podane CLSN
if nargin==3,
if nargout==0,
oldsig=sig;
end
clsn=round(clsn);
smax=max(sig);
smin=min(sig);
sig=clsn*((sig-smin)./(smax-smin));
sig=fix(sig);
sig(sig==clsn)=clsn-1;
sig=(smax-smin)/(clsn-1)*sig+smin;
end
% Tworz wektor binarny w gdzie 1 oznacza ekstremum lub rwno,
% Uznaj e pierwszy i ostatni punkt to ekstremum
w1=diff(sig);
w=logical([1;(w1(1:end-1).*w1(2:end))<=0;1]);
ext=sig(w);
if TimeAnalize,
if length(dt)==1,
exttime=(find(w==1)-1).*dt;
else
exttime=dt(w);
end
end
% Usuwam potrjne wartoci
w1=diff(ext);
w=~logical([0; w1(1:end-1)==0 & w1(2:end)==0; 0]);
ext=ext(w);
if TimeAnalize,
exttime=exttime(w);
end
% Usuwam podwjne wartoci i przesuwam czas na rodek
w=~logical([0; ext(1:end-1)==ext(2:end)]);
ext=ext(w);
if TimeAnalize,
w1=(exttime(2:end)-exttime(1:end-1))./2;
exttime=[exttime(1:end-1)+w1.*~w(2:end); exttime(end)];
exttime=exttime(w);
end
% Jeszcze raz sprawdzam ekstrema
if length(ext)>2, % warunek: w tym momencie moe ju by mao punktw
w1=diff(ext);
w=logical([1; w1(1:end-1).*w1(2:end)<0; 1]);
ext=ext(w);
if TimeAnalize,
exttime=exttime(w);
end
end
if nargout==0,
if length(dt)==1,
dt=(0:length(sig)-1).*dt;
end
if nargin==3,
plot(dt,oldsig,'b-',dt,sig,'g-',exttime,ext,'ro')
legend('signal','singal divided in classes','extrema')
else
plot(dt,sig,'b-',exttime,ext,'ro')
legend('signal','extrema')
end
xlabel('time')
ylabel('signal & extrema')
clear ext exttime
end