The definitions of `B, T, C `

https://github.com/karpathy/minGPT/blob/4050db60409b5bbaaa3302cee1e49847fc145c65/mingpt/model.py#L62

and referred from http://jalammar.github.io/illustrated-gpt2/

I am remain confused about the definitions of B, T, C = x.size().

vocabulary length, batch_size, and tokenizer size, etc?

Thanks.