docstr: Gets called when a stage (either training, validation, test) starts.
docstr_tok: ["Gets","called","when","a","stage","(","either","training",",","validation",",","test",")","starts","."]
code: def on_stage_start(self, stage, epoch):
      "Gets called when a stage (either training, validation, test) starts."
      self.ctc_metrics = self.hparams.ctc_stats()
  
      if stage != sb.Stage.TRAIN:
          self.per_metrics = self.hparams.per_stats()
  
file_path: speechbrain/recipes/Voicebank/ASR/CTC/train.py
imports: import os
  import sys
  import torch
  import speechbrain
  from speechbrain.utils.distributed import run_on_main
  from hyperpyyaml import load_hyperpyyaml
label_desc: Use image node_id 3 for calling the ASR_Brain obj's underlying member method code with example usage: obj.on_stage_start(stage, epoch) without return types