Completed
Pull Request — master (#858)
by Eddie
02:03
created

zipline.gens.AlgorithmSimulator._process_snapshot()   F

Complexity

Conditions 34

Size

Total Lines 158

Duplication

Lines 0
Ratio 0 %
Metric Value
cc 34
dl 0
loc 158
rs 2

3 Methods

Rating   Name   Duplication   Size   Complexity  
A zipline.gens.AlgorithmSimulator._get_daily_message() 0 8 1
A zipline.gens.AlgorithmSimulator._get_minute_message() 0 14 2
A zipline.gens.AlgorithmSimulator.handle_benchmark() 0 3 1

How to fix   Long Method    Complexity   

Long Method

Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.

For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.

Commonly applied refactorings include:

Complexity

Complex classes like zipline.gens.AlgorithmSimulator._process_snapshot() often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.

Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.

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#
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# Copyright 2015 Quantopian, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#     http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from logbook import Logger, Processor
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from pandas.tslib import normalize_date
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from zipline.protocol import BarData
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from zipline.utils.api_support import ZiplineAPI
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from zipline.gens.sim_engine import (
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    BAR,
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    DAY_START,
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    DAY_END,
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    MINUTE_END
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)
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log = Logger('Trade Simulation')
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class AlgorithmSimulator(object):
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    EMISSION_TO_PERF_KEY_MAP = {
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        'minute': 'minute_perf',
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        'daily': 'daily_perf'
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    }
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    def __init__(self, algo, sim_params, data_portal, clock, benchmark_source):
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        # ==============
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        # Simulation
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        # Param Setup
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        # ==============
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        self.sim_params = sim_params
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        self.env = algo.trading_environment
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        self.data_portal = data_portal
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        # ==============
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        # Algo Setup
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        # ==============
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        self.algo = algo
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        self.algo_start = normalize_date(self.sim_params.first_open)
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        # ==============
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        # Snapshot Setup
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        # ==============
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        # The algorithm's data as of our most recent event.
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        # We want an object that will have empty objects as default
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        # values on missing keys.
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        self.current_data = self._create_bar_data()
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        # We don't have a datetime for the current snapshot until we
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        # receive a message.
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        self.simulation_dt = None
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        self.clock = clock
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        self.benchmark_source = benchmark_source
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        # =============
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        # Logging Setup
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        # =============
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        # Processor function for injecting the algo_dt into
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        # user prints/logs.
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        def inject_algo_dt(record):
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            if 'algo_dt' not in record.extra:
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                record.extra['algo_dt'] = self.simulation_dt
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        self.processor = Processor(inject_algo_dt)
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    def _create_bar_data(self):
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        return BarData(
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            data_portal=self.data_portal,
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            simulator=self
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        )
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    def transform(self):
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        """
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        Main generator work loop.
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        """
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        algo = self.algo
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        algo.data_portal = self.data_portal
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        handle_data = algo.event_manager.handle_data
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        current_data = self.current_data
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        data_portal = self.data_portal
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        # can't cache a pointer to algo.perf_tracker because we're not
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        # guaranteed that the algo doesn't swap out perf trackers during
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        # its lifetime.
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        # likewise, we can't cache a pointer to the blotter.
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        algo.perf_tracker.position_tracker.data_portal = data_portal
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        def every_bar(dt_to_use):
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            # called every tick (minute or day).
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            self.simulation_dt = dt_to_use
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            algo.on_dt_changed(dt_to_use)
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            blotter = algo.blotter
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            perf_tracker = algo.perf_tracker
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            # handle any transactions and commissions coming out new orders
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            # placed in the last bar
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            new_transactions, new_commissions = \
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                blotter.get_transactions(data_portal)
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            for transaction in new_transactions:
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                perf_tracker.process_transaction(transaction)
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                # since this order was modified, record it
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                order = blotter.orders[transaction.order_id]
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                perf_tracker.process_order(order)
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            if new_commissions:
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                for commission in new_commissions:
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                    perf_tracker.process_commission(commission)
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            handle_data(algo, current_data, dt_to_use)
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            # grab any new orders from the blotter, then clear the list.
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            # this includes cancelled orders.
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            new_orders = blotter.new_orders
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            blotter.new_orders = []
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            # if we have any new orders, record them so that we know
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            # in what perf period they were placed.
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            if new_orders:
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                for new_order in new_orders:
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                    perf_tracker.process_order(new_order)
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            self.algo.portfolio_needs_update = True
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            self.algo.account_needs_update = True
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            self.algo.performance_needs_update = True
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        def once_a_day(midnight_dt):
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            # set all the timestamps
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            self.simulation_dt = midnight_dt
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            algo.on_dt_changed(midnight_dt)
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            data_portal.current_day = midnight_dt
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            # call before trading start
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            algo.before_trading_start(current_data)
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            perf_tracker = algo.perf_tracker
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            # handle any splits that impact any positions or any open orders.
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            sids_we_care_about = \
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                list(set(list(perf_tracker.position_tracker.positions.keys()) +
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                         list(algo.blotter.open_orders.keys())))
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            if len(sids_we_care_about) > 0:
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                splits = data_portal.get_splits(sids_we_care_about,
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                                                midnight_dt)
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                if len(splits) > 0:
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                    algo.blotter.process_splits(splits)
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                    perf_tracker.position_tracker.handle_splits(splits)
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        def handle_benchmark(date):
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            algo.perf_tracker.all_benchmark_returns[date] = \
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                self.benchmark_source.get_value(date)
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        with self.processor, ZiplineAPI(self.algo):
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            for dt, action in self.clock:
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                if action == BAR:
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                    every_bar(dt)
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                elif action == DAY_START:
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                    once_a_day(dt)
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                elif action == DAY_END:
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                    # End of the day.
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                    handle_benchmark(normalize_date(dt))
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                    yield self._get_daily_message(dt, algo, algo.perf_tracker)
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                elif action == MINUTE_END:
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                    handle_benchmark(dt)
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                    minute_msg, daily_msg = \
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                        self._get_minute_message(dt, algo, algo.perf_tracker)
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                    yield minute_msg
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                    if daily_msg:
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                        yield daily_msg
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        risk_message = algo.perf_tracker.handle_simulation_end()
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        yield risk_message
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    @staticmethod
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    def _get_daily_message(dt, algo, perf_tracker):
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        """
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        Get a perf message for the given datetime.
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        """
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        perf_message = perf_tracker.handle_market_close_daily(dt)
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        perf_message['daily_perf']['recorded_vars'] = algo.recorded_vars
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        return perf_message
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    @staticmethod
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    def _get_minute_message(dt, algo, perf_tracker):
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        """
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        Get a perf message for the given datetime.
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        """
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        rvars = algo.recorded_vars
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        minute_message, daily_message = perf_tracker.handle_minute_close(dt)
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        minute_message['minute_perf']['recorded_vars'] = rvars
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        if daily_message:
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            daily_message["daily_perf"]["recorded_vars"] = rvars
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        return minute_message, daily_message
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