code: def log_t(self, epsilon):
      return -0.5 * tf.log(2 * np.pi) - 0.5 * epsilon**2
  
file_path: cornac/cornac/models/pcrl/pcrl.py
imports: import numpy
  import scipy.sparse
  import scipy
  import tensorflow
label_desc: Use image node_id 4 for calling the PCRL_ obj's underlying member method code with example usage: obj.log_t(epsilon) and returns: unknown