from sympy import *
from spb import *
z, u = symbols("z u")
plot_complex_vector(
     log(gamma(u * z)), (z, -5 - 5j, 5 + 5j),
     params={u: (1, 0, 2)}, n=20, grid=False, use_latex=False,
     quiver_kw=dict(color="orange", headwidth=4))