backgammon/network.py

import tensorflow as tf
import numpy as np
from board import Board
import os
import time
import sys
import random
from eval import Eval
import glob
from operator import itemgetter
import tensorflow.contrib.eager as tfe

class Network:
    # board_features_quack has size 28
    # board_features_quack_fat has size 30
    # board_features_tesauro has size 198

    board_reps = {
        'quack-fat'   : (30, Board.board_features_quack_fat),
        'quack'       : (28, Board.board_features_quack),
        'tesauro'     : (198, Board.board_features_tesauro),
        'quack-norm'  : (30, Board.board_features_quack_norm),
        'tesauro-poop': (198, Board.board_features_tesauro_wrong)
    }

    def custom_tanh(self, x, name=None):
        return tf.scalar_mul(tf.constant(2.00), tf.tanh(x, name))

    def __init__(self, config, name):
        """
        :param config:
        :param name:
        """
        tf.enable_eager_execution()

        xavier_init = tf.contrib.layers.xavier_initializer()

        self.config = config
        self.checkpoint_path = os.path.join(config['model_storage_path'], config['model'])

        self.name = name

        # Set board representation from config
        self.input_size, self.board_trans_func = Network.board_reps[
            self.config['board_representation']
        ]
        self.output_size = 1
        self.hidden_size = 40
        self.max_learning_rate = 0.1
        self.min_learning_rate = 0.001

        # Restore trained episode count for model
        episode_count_path = os.path.join(self.checkpoint_path, "episodes_trained")
        if os.path.isfile(episode_count_path):
            with open(episode_count_path, 'r') as f:
                self.episodes_trained = int(f.read())
        else:
            self.episodes_trained = 0

        global_step_path = os.path.join(self.checkpoint_path, "global_step")
        if os.path.isfile(global_step_path):
            with open(global_step_path, 'r') as f:
                self.global_step = int(f.read())
        else:
            self.global_step = 0


        self.model = tf.keras.Sequential([
            tf.keras.layers.Dense(40, activation="sigmoid", kernel_initializer=xavier_init,
                                  input_shape=(1,self.input_size)),
            tf.keras.layers.Dense(1, activation="sigmoid", kernel_initializer=xavier_init)
        ])


    def exp_decay(self, max_lr, global_step, decay_rate, decay_steps):
        """
        Calculates the exponential decay on a learning rate
        :param max_lr: The learning rate that the network starts at
        :param global_step: The global step
        :param decay_rate: The rate at which the learning rate should decay
        :param decay_steps: The amount of steps between each decay
        :return: The result of the exponential decay performed on the learning rate
        """
        res = max_lr * decay_rate**(global_step // decay_steps)
        return res

    def do_backprop(self, prev_state, value_next):
        """
        Performs the Temporal-difference backpropagation step on the model
        :param prev_state: The previous state of the game, this has its value recalculated
        :param value_next: The value of the current move
        :return: Nothing, the calculation is performed on the model of the network
        """
        self.learning_rate = tf.maximum(self.min_learning_rate,
                                         self.exp_decay(self.max_learning_rate, self.global_step, 0.96, 50000),
                                         name="learning_rate")

        with tf.GradientTape() as tape:
            value = self.model(prev_state.reshape(1,-1))
        grads = tape.gradient(value, self.model.variables)

        difference_in_values = tf.reshape(tf.subtract(value_next, value, name='difference_in_values'), [])
        tf.summary.scalar("difference_in_values", tf.abs(difference_in_values))

        with tf.variable_scope('apply_gradients'):
            for grad, train_var in zip(grads, self.model.variables):
                backprop_calc = self.learning_rate * difference_in_values * grad
                train_var.assign_add(backprop_calc)



    def print_variables(self):
        """
        Prints all the variables of the model
        :return:
        """
        variables = self.model.variables
        for k in variables:
            print(k)

    def eval_state(self, state):
        """
        Evaluates a single state
        :param state:
        :return:
        """
        return self.model(state.reshape(1,-1))

    def save_model(self, episode_count):
        """
        Saves the model of the network, it references global_step as self.global_step
        :param episode_count:
        :return:
        """
        tfe.Saver(self.model.variables).save(os.path.join(self.checkpoint_path, 'model.ckpt'))
        #self.saver.save(sess, os.path.join(self.checkpoint_path, 'model.ckpt'), global_step=global_step)
        with open(os.path.join(self.checkpoint_path, "episodes_trained"), 'w+') as f:
            print("[NETWK] ({name}) Saving model to:".format(name=self.name),
                  os.path.join(self.checkpoint_path, 'model.ckpt'))
            f.write(str(episode_count) + "\n")

        with open(os.path.join(self.checkpoint_path, "global_step"), 'w+') as f:
            print("[NETWK] ({name}) Saving global step to:".format(name=self.name),
                  os.path.join(self.checkpoint_path, 'model.ckpt'))
            f.write(str(self.global_step) + "\n")
        if self.config['verbose']:
            self.print_variables()


    def calc_vals(self, states):
        """
        :param states:
        :return:
        """
        values = self.model.predict_on_batch(states)
        return values


    def restore_model(self):
        """
        Restore a model for a session, such that a trained model and either be further trained or
        used for evaluation

        :param sess: Current session
        :return: Nothing. It's a side-effect that a model gets restored for the network.
        """

        if glob.glob(os.path.join(self.checkpoint_path, 'model.ckpt*.index')):
        
            latest_checkpoint = tf.train.latest_checkpoint(self.checkpoint_path)
            print("[NETWK] ({name}) Restoring model from:".format(name=self.name),
                  str(latest_checkpoint))
            tfe.Saver(self.model.variables).restore(latest_checkpoint)

            # variables_names = [v.name for v in self.model.variables]


            # Restore trained episode count for model
            episode_count_path = os.path.join(self.checkpoint_path, "episodes_trained")
            if os.path.isfile(episode_count_path):
                with open(episode_count_path, 'r') as f:
                    self.config['start_episode'] = int(f.read())

            global_step_path = os.path.join(self.checkpoint_path, "global_step")
            if os.path.isfile(global_step_path):
                with open(global_step_path, 'r') as f:
                    self.config['global_step'] = int(f.read())

            if self.config['verbose']:
                self.print_variables()



    def make_move(self, board, roll, player):
        """
        Find the best move given a board, roll and a player, by finding all possible states one can go to
        and then picking the best, by using the network to evaluate each state. The highest score is picked
        for the 1-player and the max(1-score) is picked for the -1-player.

        :param sess:
        :param board: Current board
        :param roll:  Current roll
        :param player: Current player
        :return: A pair of the best state to go to, together with the score of that state
        """
        legal_moves = list(Board.calculate_legal_states(board, player, roll))

        legal_states = [list(tmp) for tmp in legal_moves]

        legal_states = np.array([self.board_trans_func(tmp, player)[0] for tmp in legal_states])

        scores = self.model.predict_on_batch(legal_states)
        transformed_scores = [x if np.sign(player) > 0 else 1 - x for x in scores]

        best_score_idx = np.argmax(np.array(transformed_scores))
        best_move = legal_moves[best_score_idx]
        best_score = scores[best_score_idx]

        return [best_move, best_score]

    def make_move_n_ply(self, sess, board, roll, player, n = 1):
        """

        :param sess:
        :param board:
        :param roll:
        :param player:
        :param n:
        :return:
        """
        best_pair = self.calc_n_ply(n, sess, board, player, roll)
        return best_pair


    def calculate_1_ply(self, board, roll, player):
        """
        Find the best move based on a 1-ply look-ahead. First the best move is found for a single ply and then an
        exhaustive search is performed on the best 15 moves from the single ply.

        :param sess:
        :param board:
        :param roll: The original roll
        :param player: The current player
        :return: Best possible move based on 1-ply look-ahead

        """

        # find all legal states from the given board and the given roll
        init_legal_states = Board.calculate_legal_states(board, player, roll)


        legal_moves = list(Board.calculate_legal_states(board, player, roll))

        legal_states = [list(tmp) for tmp in legal_moves]

        legal_states = np.array([self.board_trans_func(tmp, player)[0] for tmp in legal_states])

        scores = self.calc_vals(legal_states)
        scores = [score.numpy() for score in scores]

        moves_and_scores = list(zip(init_legal_states, scores))

        sorted_moves_and_scores = sorted(moves_and_scores, key=itemgetter(1), reverse=player==1)

        best_boards = [x[0] for x in sorted_moves_and_scores[:10]]



        scores, trans_scores = self.do_ply(best_boards, player)

        best_score_idx = np.array(trans_scores).argmax()

        return [best_boards[best_score_idx], scores[best_score_idx]]

    def do_ply(self, boards, player):
        """
        Calculates a single extra ply, resulting in a larger search space for our best move.
        This is somewhat hardcoded to only do a single ply, seeing that it calls max on all scores, rather than
        allowing the function to search deeper, which could result in an even larger search space. If we wish
        to have more than 2-ply, this should be fixed, so we could extend this method to allow for 3-ply.

        :param sess:
        :param boards: The boards to try all rolls on
        :param player: The player of the previous ply
        :return: An array of scores where each index describes one of the boards which was given as param
        to this function.
        """

        import time

        def gen_21_rolls():
            """
            Calculate all possible rolls, [[1,1], [1,2] ..]
            :return: All possible rolls
            """
            a = []
            for x in range(1, 7):
                for y in range(1, 7):
                    if not [x, y] in a and not [y, x] in a:
                        a.append([x, y])

            return a

        all_rolls = gen_21_rolls()

        start = time.time()

        list_of_moves = []

        for idx, board in enumerate(boards):
            all_board_moves = []
            for roll in all_rolls:
                all_states = list(Board.calculate_legal_states(board, player*-1, roll))
                for state in all_states:
                    state = np.array(self.board_trans_func(state, player*-1)[0])
                    all_board_moves.append(state)
            list_of_moves.append(np.array(all_board_moves))


        all_scores = [self.model.predict_on_batch(board) for board in list_of_moves]
        transformed_scores = [x if player == 1 else (1-x) for x in all_scores]

        scores_means = [tf.reduce_mean(score) for score in all_scores]
        transformed_means = [tf.reduce_mean(score) for score in transformed_scores]


        return ([scores_means, transformed_means])


        print(time.time() - start)

        # count = 0
        # # loop over boards
        # for a_board in boards:
        #     a_board_scores = []
        #
        #     # loop over all rolls, for each board
        #     for roll in all_rolls:
        #
        #         # find all states we can get to, given the board and roll and the opposite player
        #         all_rolls_boards = Board.calculate_legal_states(a_board, player*-1, roll)
        #         count += len(all_rolls_boards)
        #         # find scores for each board found above
        #         spec_roll_scores = [self.eval_state(sess, self.board_trans_func(new_board, player*-1))
        #                             for new_board in all_rolls_boards]
        #
        #         # if the original player is the -1 player, then we need to find (1-value)
        #         spec_roll_scores = [x if player == 1 else (1-x) for x in spec_roll_scores]
        #
        #         # find the best score
        #         best_score = max(spec_roll_scores)
        #
        #         # append the best score to a_board_scores, where we keep track of the best score for each board
        #         a_board_scores.append(best_score)
        #
        #     # save the expected average of board scores
        #     all_rolls_scores.append(sum(a_board_scores)/len(a_board_scores))
        #
        # # return all the average scores
        # print(count)
        # return all_rolls_scores


    def calc_n_ply(self, n_init, sess, board, player, roll):
        """

        :param n_init:
        :param sess:
        :param board:
        :param player:
        :param roll:
        :return:
        """

        # find all legal states from the given board and the given roll
        init_legal_states = Board.calculate_legal_states(board, player, roll)

        # find all values for the above boards
        zero_ply_moves_and_scores = [(move, self.eval_state(sess, self.board_trans_func(move, player))) for move in init_legal_states]

        # pythons reverse is in place and I can't call [:15] on it, without applying it to an object like so. Fuck.
        sorted_moves_and_scores = sorted(zero_ply_moves_and_scores, key=itemgetter(1), reverse=player==1)


        best_boards = [x[0] for x in sorted_moves_and_scores[:10]]

        best_move_score_pair = self.n_ply(n_init, sess, best_boards, player)

        return best_move_score_pair


    def n_ply(self, n_init, sess, boards_init, player_init):
        """

        :param n_init:
        :param sess:
        :param boards_init:
        :param player_init:
        :return:
        """
        def ply(n, boards, player):
            def calculate_possible_states(board):
                possible_rolls = [ (1, 1), (1, 2), (1, 3), (1, 4), (1, 5),
                                   (1, 6), (2, 2), (2, 3), (2, 4), (2, 5),
                                   (2, 6), (3, 3), (3, 4), (3, 5), (3, 6),
                                   (4, 4), (4, 5), (4, 6), (5, 5), (5, 6),
                                   (6, 6) ]

                # for roll in possible_rolls:
                #     print(len(Board.calculate_legal_states(board, player, roll)))

                return [ Board.calculate_legal_states(board, player, roll)
                         for roll
                         in  possible_rolls ]

            def find_best_state_score(boards):
                score_pairs = [ (board, self.eval_state(sess, self.board_trans_func(board, player)))
                                for board
                                in  boards ]
                scores = [ pair[1]
                           for pair
                           in score_pairs ]
                best_score_pair = score_pairs[np.array(scores).argmax()]

                return best_score_pair

            def average_score(boards):
                return sum(boards)/len(boards)

            def average_ply_score(board):
                states_for_rolls = calculate_possible_states(board)

                best_state_score_for_each_roll = [
                    find_best_state_score(states)
                    for states
                    in  states_for_rolls ]
                best_score_for_each_roll = [ x[1]
                                             for x
                                             in best_state_score_for_each_roll ]

                average_score_var = average_score(best_score_for_each_roll)
                return average_score_var


            if n == 1:
                average_score_pairs = [ (board, average_ply_score(board))
                                        for board
                                        in  boards ]
                return average_score_pairs
            elif n > 1: # n != 1
                def average_for_score_pairs(score_pairs):
                    scores = [ pair[1]
                               for pair
                               in score_pairs ]
                    return sum(scores)/len(scores)

                def average_plain(scores):
                    return sum(scores)/len(scores)

                print("+"*20)
                print(n)
                print(type(boards))
                print(boards)
                possible_states_for_boards = [
                    (board, calculate_possible_states(board))
                    for board
                    in  boards ]

                average_score_pairs = [
                    (inner_boards[0], average_plain([ average_for_score_pairs(ply(n - 1, inner_board, player * -1 if n == 1 else player))
                                                      for inner_board
                                                      in  inner_boards[1] ]))
                    for inner_boards
                    in  possible_states_for_boards ]

                return average_score_pairs

            else:
                assert False

        if n_init < 1: print("Unexpected argument n = {}".format(n_init)); exit()

        boards_with_scores = ply(n_init, boards_init, -1 * player_init)
        #print("Boards with scores:",boards_with_scores)
        scores = [ ( pair[1] if player_init == 1 else (1 - pair[1]) )
                   for pair
                   in boards_with_scores ]
        #print("All the scores:",scores)
        best_score_pair = boards_with_scores[np.array(scores).argmax()]
        return best_score_pair


    def eval(self, episode_count, trained_eps = 0):
        """
        Used to evaluate a model. Can either use pubeval, a model playing at an intermediate level, or dumbeval
        a model which has been given random weights, so it acts deterministically random.

        :param episode_count: The amount of episodes to run
        :param trained_eps:   The amount of episodes the model we want to evaluate, has trained
        :param tf_session:
        :return: outcomes:    The outcomes of the evaluation session
        """

        def do_eval(method, episodes = 1000, trained_eps = 0):
            """
            Do the actual evaluation

            :param sess:
            :param method:     Either pubeval or dumbeval
            :param episodes:   Amount of episodes to use in the evaluation
            :param trained_eps:
            :return: outcomes : Described above
            """

            start_time = time.time()

            def print_time_estimate(eps_completed):
                cur_time = time.time()
                time_diff = cur_time - start_time
                eps_per_sec = eps_completed / time_diff
                secs_per_ep = time_diff / eps_completed
                eps_remaining = (episodes - eps_completed)
                sys.stderr.write(
                    "[EVAL ] Averaging {per_sec} episodes per second\n".format(per_sec=round(eps_per_sec, 2)))
                sys.stderr.write(
                    "[EVAL ] {eps_remaining} episodes remaining; approx. {time_remaining} seconds remaining\n".format(
                        eps_remaining=eps_remaining, time_remaining=int(eps_remaining * secs_per_ep)))

            sys.stderr.write(
                "[EVAL ] Evaluating {eps} episode(s) with method '{method}'\n".format(eps=episodes, method=method))


            if method == 'pubeval':
                outcomes = []
                for i in range(1, episodes + 1):
                    sys.stderr.write("[EVAL ] Episode {}".format(i))
                    board = Board.initial_state
                    while Board.outcome(board) is None:
                        roll = (random.randrange(1, 7), random.randrange(1, 7))

                        board = (self.make_move(board, roll, 1))[0]

                        roll = (random.randrange(1, 7), random.randrange(1, 7))

                        board = Eval.make_pubeval_move(board, -1, roll)[0][0:26]

                    sys.stderr.write("\t outcome {}".format(Board.outcome(board)[1]))
                    outcomes.append(Board.outcome(board)[1])
                    sys.stderr.write("\n")

                    if i % 10 == 0:
                        print_time_estimate(i)

                return outcomes

            elif method == 'dumbeval':
                outcomes = []
                for i in range(1, episodes + 1):
                    sys.stderr.write("[EVAL ] Episode {}".format(i))
                    board = Board.initial_state
                    while Board.outcome(board) is None:
                        roll = (random.randrange(1, 7), random.randrange(1, 7))

                        board = (self.make_move(board, roll, 1))[0]

                        roll = (random.randrange(1, 7), random.randrange(1, 7))

                        board = Eval.make_dumbeval_move(board, -1, roll)[0][0:26]

                    sys.stderr.write("\t outcome {}".format(Board.outcome(board)[1]))
                    outcomes.append(Board.outcome(board)[1])
                    sys.stderr.write("\n")

                    if i % 10 == 0:
                        print_time_estimate(i)

                return outcomes

            else:
                sys.stderr.write("[EVAL ] Evaluation method '{}' is not defined\n".format(method))
                return [0]
            

        outcomes = [ (method, do_eval(method,
                                      episode_count,
                                      trained_eps = trained_eps))
                     for method
                     in self.config['eval_methods'] ]
        return outcomes


    def train_model(self, episodes=1000, save_step_size=100, trained_eps=0):
        """

        :param episodes:
        :param save_step_size:
        :param trained_eps:
        :return:
        """
        with tf.Session() as sess:
            difference_in_vals = 0

            self.restore_model()

            start_time = time.time()

            def print_time_estimate(eps_completed):
                cur_time = time.time()
                time_diff = cur_time - start_time
                eps_per_sec = eps_completed / time_diff
                secs_per_ep = time_diff / eps_completed
                eps_remaining = (episodes - eps_completed)
                sys.stderr.write(
                    "[TRAIN] Averaging {per_sec} episodes per second\n".format(per_sec=round(eps_per_sec, 2)))
                sys.stderr.write(
                    "[TRAIN] {eps_remaining} episodes remaining; approx. {time_remaining} seconds remaining\n".format(
                        eps_remaining=eps_remaining, time_remaining=int(eps_remaining * secs_per_ep)))

            sys.stderr.write("[TRAIN] Training {} episodes and save_step_size {}\n".format(episodes, save_step_size))
            outcomes = []
            for episode in range(1, episodes + 1):

                sys.stderr.write("[TRAIN] Episode {}".format(episode + trained_eps))
                # TODO decide which player should be here

                player = 1
                prev_board = Board.initial_state
                i = 0
                while Board.outcome(prev_board) is None:
                    i += 1
                    self.global_step += 1


                    cur_board, cur_board_value = self.make_move(prev_board,
                                                                (random.randrange(1, 7), random.randrange(1, 7)),
                                                                player)

                    difference_in_vals += abs((cur_board_value - self.eval_state(self.board_trans_func(prev_board, player))))

                    if self.config['verbose']:
                        print("Difference in values:", difference_in_vals)
                        print("Current board value :", cur_board_value)
                        print("Current board is    :\n",cur_board)


                    # adjust weights
                    if Board.outcome(cur_board) is None:
                        self.do_backprop(self.board_trans_func(prev_board, player), cur_board_value)
                        player *= -1

                    prev_board = cur_board

                final_board = prev_board
                sys.stderr.write("\t outcome {}\t turns {}".format(Board.outcome(final_board)[1], i))
                outcomes.append(Board.outcome(final_board)[1])
                final_score = np.array([Board.outcome(final_board)[1]])
                scaled_final_score = ((final_score + 2) / 4)

                self.do_backprop(self.board_trans_func(prev_board, player), scaled_final_score.reshape(1,1))

                sys.stderr.write("\n")

                if episode % min(save_step_size, episodes) == 0:
                    sys.stderr.write("[TRAIN] Saving model...\n")
                    self.save_model(episode + trained_eps)

                if episode % 50 == 0:
                    print_time_estimate(episode)

            sys.stderr.write("[TRAIN] Saving model for final episode...\n")
            self.save_model(episode+trained_eps)

            return outcomes, difference_in_vals[0][0]