You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: adiShifts.m
    path of file: ./repos/chebfun/@chebop2
    
    the code of the file until where you have to start completion: function [p, q] = adiShifts(a, b, c, d, tol)
%ADISHIFTS  ADI shifts for solving AX-XB=F.
% [P, Q] = ADISHIFTS(a, b, c, d, TOL) returns the optimal ADI shifts for
% solving AX-XB = F with the ADI method when A and B have eigenvalues lying
% in [a,b] and [c,d], respectively. WLOG, we require that a<b<c<d and
% 0<tol<1.

gam = (c-a)*(d-b)/(c-b)/(d-a);                 % Cross-ratio of a,b,c,d
% Calculate Mobius transform T:{-alp,-1,1,alp}->{a,b,c,d} for some alp:
alp = -1 + 2*gam + 2*sqrt(gam^2-gam);          % Mobius exists with this t

    
function [p, q] = adiShifts(a, b, c, d, tol)
%ADISHIFTS  ADI shifts for solving AX-XB=F.
% [P, Q] = ADISHIFTS(a, b, c, d, TOL) returns the optimal ADI shifts for
% solving AX-XB = F with the ADI method when A and B have eigenvalues lying
% in [a,b] and [c,d], respectively. WLOG, we require that a<b<c<d and
% 0<tol<1.

gam = (c-a)*(d-b)/(c-b)/(d-a);                 % Cross-ratio of a,b,c,d
% Calculate Mobius transform T:{-alp,-1,1,alp}->{a,b,c,d} for some alp:
alp = -1 + 2*gam + 2*sqrt(gam^2-gam);          % Mobius exists with this t
A = det([-a*alp a 1; -b b 1 ; c c 1]);         % Determinant formulae for Mobius
B = det([-a*alp -alp a; -b -1 b ; c 1 c]);
C = det([-alp a 1; -1 b 1 ; 1 c 1]);
D = det([-a*alp -alp 1; -b -1 1; c 1 1]);
T = @(z) (A*z+B)./(C*z+D);                     % Mobius transfom
J = ceil( log(16*gam)*log(4/tol)/pi^2 );       % Number of ADI iterations
if ( alp > 1e7 )
    K = (2*log(2)+log(alp)) + (-1+2*log(2)+log(alp))/alp^2/4;
    m1 = 1/alp^2;
    u = (1/2:J-1/2)*K/J;
    dn = sech(u) + .25*m1*(sinh(u).*cosh(u)+u).*tanh(u).*sech(u);
else
    K = ellipke( 1-1/alp^2 );
    [~, ~, dn] = ellipj((1/2:J-1/2)*K/J,1-1/alp^2); % ADI shifts for [-1,-1/t]&[1/t,1]
end