class_docstr: Length Regulator
docstr: Forward pass through the length regulator module.
  
  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 forward(self, x, duration, use_state_info=False):
      """Forward pass through the length regulator module.
  
      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,).
      """
  
      if duration.sum() == 0:
          logging.warning(
              "predicted durations includes all 0 sequences. "
              "fill the first element with 1."
          )
          duration[duration.sum(dim=1).eq(0)] = 1
  
      output, mel_len = self.LR(
          x, duration, use_state_info=use_state_info
      )
  
      return output, 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 4 for calling the LengthRegulator obj's underlying member method code with example usage: obj.forward(x, duration, use_state_info) and returns: output,  mel_len