'Given observations, old actions, and distribution of old actions, return a symbolically reparameterized
representation of the actions in terms of the policy parameters
:param obs_var:
:param action_var:
:param old_dist_info_vars:
:return:'

def get_reparam_action_sym(self, obs_var, action_var, old_dist_info_vars):

    new_dist_info_vars = self.dist_info_sym(obs_var, action_var)
    (new_mean_var, new_log_std_var) = (new_dist_info_vars['mean'], new_dist_info_vars['log_std'])
    (old_mean_var, old_log_std_var) = (old_dist_info_vars['mean'], old_dist_info_vars['log_std'])
    epsilon_var = ((action_var - old_mean_var) / (tf.exp(old_log_std_var) + 1e-08))
    new_action_var = (new_mean_var + (epsilon_var * tf.exp(new_log_std_var)))
    return new_action_var
