code: def ProbsRatio(dist_inputs, actions, old_log_probs, log_prob_fun):
      """Probability Ratio from the PPO algorithm."""
      # dist_inputs of the shape float32[128,1,18]
      # actions of the shape int32[128,1]
      # and old_log_probs of the shape float32[128,1]
      new_log_probs = NewLogProbs(dist_inputs, actions, log_prob_fun)
      assert new_log_probs.shape == old_log_probs.shape, (
          f"new_log_probs.shape was {new_log_probs.shape} and"
          f"old_log_probs.shape was {old_log_probs.shape}"
      )
      # The ratio between new_probs and old_probs expressed
      # using log_probs and exponentiation
      probs_ratio = jnp.exp(new_log_probs - old_log_probs)
      return probs_ratio
  
file_path: trax/trax/rl/rl_layers.py
imports: from trax.fastmath import numpy
label_desc: Use image node_id 6 for calling a global function with example usage: ProbsRatio(dist_inputs, actions, old_log_probs, log_prob_fun) and returns: probs_ratio