blocked_randomization.py

"""
Generates an array blocks * block_len long, containing 1 and 2.
It's shuffled such that there can never be more than block_len
consecutive repetitions of either value.
"""
import numpy as np

blocks = 100
block_len = 8
groupnums = (np.arange(blocks * block_len) % 2) + 1
blocked = groupnums.reshape(blocks, block_len)
np.apply_along_axis(np.random.shuffle, 1, blocked)
groups = blocked.reshape(blocks * block_len)