module 

def mem(nmax, mmx, dt, g, f, e, pm)
f[0] = 1/((nmax-1)*dt)
  for i in 1..nmax
    f[i] << f[0]*(i-1)
    sum = 1.0
    ci  = Complex(0.0, 1.0)*Math::PI*2*F(i)*dt
    for j in 1..nmax
      sum = sum + g(j)*Math*exp(-ci*j)
    end
    e[i] = 2*pm*dt/(sum.abs**2)
  end
end