f = @(x) (0).*((x < -d/2)) + (1/sqrt(d)*(cos(p*x)).*((-d/2 <= x) & (x <= d/2)) + (0).*(d/2 < x));
d = @(x) (0).*((x < -d/2)) + (imag(psi)).*((-d/2 <= x) & (x <= d/2)) + (0).*(d/2 < x);