N_FFT=8;
K_FFT=2*N_FFT+1;
epsilon=1.0e-3;
tol=1.0e-13;
K_fixed_point=100;
N_traj=2000;
Nmax=2^8;

LN=divisors(Nmax);

N_data=4;
N_proc=500;

F(u)=i*(1+real(u)^3+imag(u)^5)*u
phi(x)=2*real(x[1])+4*imag(x[1])