from otree.api import * import time import random doc = "Double auction market" class Constants(BaseConstants): name_in_url = 'double_auction' players_per_group = None num_rounds = 1 items_per_seller = 3 valuation_min = cu(50) valuation_max = cu(110) production_costs_min = cu(10) production_costs_max = cu(80) class Subsession(BaseSubsession): pass def creating_session(subsession: Subsession): players = subsession.get_players() for p in players: # for more buyers, change the 2 to 3 p.is_buyer = p.id_in_group % 2 > 0 if p.is_buyer: p.num_items = 0 p.break_even_point = random.randint(Constants.valuation_min, Constants.valuation_max) p.current_offer = 0 else: p.num_items = Constants.items_per_seller p.break_even_point = random.randint( Constants.production_costs_min, Constants.production_costs_max ) p.current_offer = Constants.valuation_max + 1 class Group(BaseGroup): start_timestamp = models.IntegerField() class Player(BasePlayer): is_buyer = models.BooleanField() current_offer = models.CurrencyField() break_even_point = models.CurrencyField() num_items = models.IntegerField() class Transaction(ExtraModel): group = models.Link(Group) buyer = models.Link(Player) seller = models.Link(Player) price = models.CurrencyField() seconds = models.IntegerField(doc="Timestamp (seconds since beginning of trading)") def find_match(buyers, sellers): for buyer in buyers: for seller in sellers: if seller.num_items > 0 and seller.current_offer <= buyer.current_offer: return [buyer, seller] def live_method(player: Player, data): group = player.group players = group.get_players() buyers = [p for p in players if p.is_buyer] sellers = [p for p in players if not p.is_buyer] news = None if data: try: offer = int(data['offer']) except Exception: print('Invalid message received', data) return player.current_offer = offer if player.is_buyer: match = find_match(buyers=[player], sellers=sellers) else: match = find_match(buyers=buyers, sellers=[player]) if match: [buyer, seller] = match price = buyer.current_offer Transaction.create( group=group, buyer=buyer, seller=seller, price=price, seconds=int(time.time() - group.start_timestamp), ) buyer.num_items += 1 seller.num_items -= 1 buyer.payoff += buyer.break_even_point - price seller.payoff += price - seller.break_even_point buyer.current_offer = 0 seller.current_offer = Constants.valuation_max + 1 news = dict(buyer=buyer.id_in_group, seller=seller.id_in_group, price=price) bids = sorted([p.current_offer for p in buyers if p.current_offer > 0], reverse=True) asks = sorted([p.current_offer for p in sellers if p.current_offer <= Constants.valuation_max]) highcharts_series = [[tx.seconds, tx.price] for tx in Transaction.filter(group=group)] return { p.id_in_group: dict( bids=bids, asks=asks, highcharts_series=highcharts_series, num_items=p.num_items, current_offer=p.current_offer, news=news, payoff=p.payoff, ) for p in players } # PAGES class WaitToStart(WaitPage): @staticmethod def after_all_players_arrive(group: Group): group.start_timestamp = int(time.time()) class Trading(Page): live_method = live_method @staticmethod def js_vars(player: Player): return dict(id_in_group=player.id_in_group, is_buyer=player.is_buyer) @staticmethod def get_timeout_seconds(player: Player): import time group = player.group return (group.start_timestamp + 2 * 60) - time.time() class ResultsWaitPage(WaitPage): pass class Results(Page): pass page_sequence = [WaitToStart, Trading, ResultsWaitPage, Results]