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Showing posts from January 25, 2019

fsolve and fimplicit for a non-linear equation

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0 $begingroup$ It's well known that from time to time nonlinear solver fsolve in Matlab gives controversial results but I'd like to ask and simultaneously share my experience of the exploitation of this command. I want to solve nonlinear equation and find a function $y=y(x)$ $-Psi(1/2) +{it Re} left( Psi left( 1/2+{ frac { left( 1+i right) tau,tanh left( left( 1+i right) x right) }{y}} right) right) +ln left( y right) =0$ where $Psi(z)$ is the digamma function of a complex argument and $tau$ is a real positive number. Here is my code in Matlab: function z=temperature dd=linspace(0,5,1000); for j=1:1000 if j==1 x0=1; else x0=temp(j-1); end z1=fsolve(@(y) self(y,dd(j)),x0,optimset('Display','off')); temp(j)=z1; end plot(dd,temp,'Color',...

Can discrete time series be non-stationary?

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1 $begingroup$ We all know about time series that grow over time, but it seems like we only ever see continuous values such as the plot shown below. But is there such thing as a time series that might start out with balanced mix of class 0 and class 1, but eventually turn into mostly class 1's? time-series stationarity share | cite | improve this question asked 4 hours ago Linas Kleiza Linas Kleiza 29 4 $endgroup$ add a comment  |  ...