code: def logpowerspec(ps, norm=1):
      """Compute the log power spectorgram features from powerspec.
  
      :param ps: power spectrum
      :param norm: If norm=1, the log power spectrum is normalised so that the max value (across all frames) is 0.
      :returns: If frames is an NxD matrix, output will be Nx(NFFT/2+1). Each row will be the log power spectrum of the corresponding frame.
      """
      ps[ps <= 1e-30] = 1e-30
      lps = 10 * numpy.log10(ps)
      if norm:
          return lps - numpy.max(lps)
      return lps
  
file_path: delta/delta/data/feat/python_speech_features/base.py
imports: from __future__ import division
  import numpy
  from scipy.fftpack import dct
  from delta.data.feat.python_speech_features import sigproc
label_desc: Use image node_id 3 for calling a global function with example usage: logpowerspec(ps, norm) and returns: lps, unknown