I check param again， I was wrong about the meaning of mult_lt=0.
I noticed that track_running_stats is a new parameter in version 0.4,  I did’t see it in previous version.
The doc said that this module tracks the running mean and variance, and when set to False, this module does not track such statistics and always uses batch statistics in both training and eval modes.
What is the meaning of “tracks the running mean and variance”? It did’t do it in previous version?