# Copyright 2018 The trfl Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or  implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============================================================================
"""Ops for computing v-trace learning targets."""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import collections

# Dependency imports
import tensorflow.compat.v1 as tf


VTraceFromLogitsReturns = collections.namedtuple(
    'VTraceFromLogitsReturns',
    ['vs', 'pg_advantages', 'log_rhos',
     'behaviour_action_log_probs', 'target_action_log_probs'])
VTraceReturns = collections.namedtuple('VTraceReturns', 'vs pg_advantages')


def log_probs_from_logits_and_actions(policy_logits, actions):
  """Computes action log-probs from policy logits and actions.

  In the notation used throughout documentation and comments, T refers to the