code: def frame_labels2posterior_mx(labels):
      # initialize from reference
      pmx = np.zeros((len(labels), labels.max() + 1))
      pmx[np.arange(len(labels)), labels] = 1
      return pmx
  
file_path: espnet/egs/libri_css/asr1/diarization/VB_diarization.py
imports: import numexpr
  import numpy
  import scipy.linalg
  from scipy.sparse import coo_matrix
label_desc: Use image node_id 3 for calling a global function with example usage: frame_labels2posterior_mx(labels) and returns: pmx