旧版热身（历史参考）

展开查看旧版代码（仅展示，不执行）

import numpy as np
z=np.ones((8,4)); print('collapsed variance',z.var(0),'pair loss',((z-z[::-1])**2).mean())
rng=np.random.default_rng(3); student=rng.normal(size=4); teacher=np.zeros(4)
for _ in range(3): teacher=.9*teacher+.1*student
print('EMA teacher',teacher.round(3),'stop-gradient is one component, not a proof')