class_docstr: read the kaldi ark format file
class_docstr_tok: ["read","the","kaldi","ark","format","file"]
docstr: compute the delta normalizer
  args:
      delta_window: the detla window
  return:
      -1: failed
      0: success
docstr_tok: ["compute","the","delta","normalizer","args",":","delta_window",":","the","detla","window","return",":","-1",":","failed","0",":","success"]
code: def _compute_delta_normalizer(self, delta_window=2):
      """
      compute the delta normalizer
      args:
          delta_window: the detla window
      return:
          -1: failed
          0: success
      """
      self._delta_normalizer = 0
      self._delta_window = delta_window
  
      self._delta_window_array = np.array(
          range(-1 * self._delta_window, self._delta_window + 1)
      )
      self._delta_normalizer = np.sum(
          np.square(self._delta_window_array)
      )
      self._delta_normalizer = 1.0 / self._delta_normalizer
      self._delta_window_array = (
          self._delta_window_array * self._delta_normalizer
      )
  
      # base method
      # for tmp_window in range(-1*delta_window, delta_window+1):
      #    self._delta_normalizer += tmp_window * tmp_window
  
      # self._delta_normalizer = 1.0 / self._delta_normalizer
      return 0
  
file_path: delta/delta/data/utils/htk_reader_lib.py
imports: import os
  import math
  import numpy
label_desc: Use image node_id 2 for calling the HtkReaderIO obj's underlying member method code with example usage: obj._compute_delta_normalizer(delta_window) and returns: int