function g = BWF(x,pos,wid,m)
% BWF (Breit-Wigner-Fano) http://en.wikipedia.org/wiki/Fano_resonance
% pos=position; wid=width; m=Fano factor
%  T. C. O'Haver, 2014
y=((m*wid/2+x-pos).^2)./(((wid/2).^2)+(x-pos).^2);
g=y./max(y);