f = 0:0.01:2;
eps = lorentzian(f,[1 0.1 2 1])+random('normal',0,0.5,1,length(f))+1i*random('normal',0,0.5,1,length(f));
oparams = fitfun(f,eps,[1.5 0.3 3 2])
epsFit = lorentzian(f,oparams);
clf;
plot(f, real(eps),'d'); hold on;
plot(f, real(epsFit)); hold on;
plot(f, imag(eps),'d','color','r'); hold on;
plot(f, imag(epsFit),'color','r');