import quantities as pq
import matplotlib.pyplot as plt
from elephant.spike_train_generation import homogeneous_poisson_process
from viziphant.statistics import plot_isi_histogram

np.random.seed(12)
population1 = [homogeneous_poisson_process(rate=30 * pq.Hz,
               t_stop=50 * pq.s) for _ in range(10)]
population2 = [homogeneous_poisson_process(rate=r * pq.Hz,
               t_stop=50 * pq.s) for r in range(1, 20)]
plot_isi_histogram([population1, population2], cutoff=250 * pq.ms,
                   legend=['population1', 'population2'])
plt.show()