class_docstr: Length Regulator
docstr: Length regulates input mel-spectrograms to match duration.
  
  Args:
      x (Tensor): Input tensor (B, dim, T).
      duration (Tensor): Duration tensor (B, T).
      use_state_info (bool, optional): Whether to use position information or not.
  
  Returns:
      Tensor: Output tensor (B, dim, D_frame).
      Tensor: Output length (B,).
code: def LR(self, x, duration, use_state_info=False):
      """Length regulates input mel-spectrograms to match duration.
  
      Args:
          x (Tensor): Input tensor (B, dim, T).
          duration (Tensor): Duration tensor (B, T).
          use_state_info (bool, optional): Whether to use position information or not.
  
      Returns:
          Tensor: Output tensor (B, dim, D_frame).
          Tensor: Output length (B,).
      """
      x = torch.transpose(x, 1, 2)
      output = list()
      mel_len = list()
      for batch, expand_target in zip(x, duration):
          expanded = self.expand(
              batch, expand_target, use_state_info=use_state_info
          )
          output.append(expanded)
          mel_len.append(expanded.shape[0])
  
      output = pad_list(output, self.pad_value)  # (B, D_frame, dim)
      output = torch.transpose(output, 1, 2)
      return output, torch.LongTensor(mel_len)
  
file_path: espnet/espnet2/gan_svs/vits/length_regulator.py
imports: import logging
  import torch
  from espnet.nets.pytorch_backend.nets_utils import pad_list
label_desc: Use image node_id 2 for calling the LengthRegulator obj's underlying member method code with example usage: obj.LR(x, duration, use_state_info) and returns: output,  torch