A training step is one gradient update. In one step batch_size
examples are processed.
An epoch consists of one full cycle through the training data. This is usually many steps. As an example, if you have 2,000 images and use a batch size of 10 an epoch consists of:
2,000 images / (10 images / step) = 200 steps.
If you choose your training image randomly (and independently) in each step, you normally do not call it epoch. [This is where my answer differs from the previous one. Also see my comment.]
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…