pool.py

npools = 4
inputs = []
for i in range(npools):
    inputs.append((rs[i::npools], T_perps_0[i::npools], T_pars_0[i::npools],
                   vs[i::npools], ns[i::npools]))

# multiprocessing pool
with Pool(npools) as p:
    anis = p.map(single_tani, inputs)

out = []
for ani in anis:
    out += ani