class_docstr: Optim wrapper that implements rate.
class_docstr_tok: ["Optim","wrapper","that","implements","rate","."]
docstr: Implement `lrate` above.
docstr_tok: ["Implement","`","lrate","`","above","."]
code: def rate(self, step=None):
      """Implement `lrate` above."""
      if step is None:
          step = self._step
      return (
          self.factor
          * self.model_size ** (-0.5)
          * min(step ** (-0.5), step * self.warmup ** (-1.5))
      )
  
file_path: espnet/espnet/nets/pytorch_backend/transformer/optimizer.py
imports: import torch
label_desc: Use image node_id 4 for calling the NoamOpt obj's underlying member method code with example usage: obj.rate(step) and returns: unknown