What is meaning of step in loss graph

Question

I find some paper (Resnet paper) has the graph as follows:

As you see, the loss gradually decreases when iterations increasing. But at some point (red arrow), the loss rapid decrease (as a step). What is this point? Is it changing learning rate point? Thanks all

Answer 1

Yes, they changed the learning rate at that point. It could be a learning rate schedule, which means decrease the learning rate by a factor every X iterations, or it could be another policy like decrease the learning rate when a plateau in the loss is detected.