%%%%%%%%% Linear Fractional Transformation on complex plane %%%%%%%%%%%%%%
%
% LFT
% Usage: L = LFT(T1,T2)
% Inputs: T1,T2 triples of distinct complex numbers       
%
% Output: A matrix in SL_2(C), which maps T1 to T2 as an LFT 

function L=lft(T1,T2)

   T1 = T1(:);  T2 = T2(:);    
   A = [ T1 -T1.*T2  ones(3,1) -T2];
   L = null(A);
   L = [L(1:2,1) L(3:4,1)];
   L = L/sqrt(det(L));