@anarchy1989
The first thing you will want to do it load your targets with your datas. I like personally to attach the target to the dataline I as I add it to backtrader.
tickers = {"FB": 0.25, "MSFT": 0.4, "TSLA": 0.35}
for ticker, target in tickers.items():
data = bt.feeds.YahooFinanceData(
dataname=ticker,
timeframe=bt.TimeFrame.Days,
fromdate=datetime.datetime(2019, 1, 1),
todate=datetime.datetime(2020, 12, 31),
reverse=False,
)
data.target = target
cerebro.adddata(data, name=ticker)
In next you will want to go through each data, and determine the current allocation. If the current allocation is too far from the desired allocation (threshold) you trade all datas.
Notice there is a buffer variable. This will reduce the overall value of the account for calculating units to trade. This helps avoid margin.
You will use a dictionary to track this information.
def next(self):
track_trades = dict()
total_value = self.broker.get_value() * (1 - self.p.buffer)
for d in self.datas:
track_trades[d] = dict()
value = self.broker.get_value(datas=[d])
allocation = value / total_value
units_to_trade = (d.target - allocation) * total_value / d.close[0]
track_trades[d]["units"] = units_to_trade
# Can check to make sure there is enough distance away from ideal to trade.
track_trades[d]["threshold"] = abs(d.target - allocation) > self.p.threshold
Check all the thresholds to determine if trading. If any of datas need trading, then all need trading.
rebalance = False
for values in track_trades.values():
if values['threshold']:
rebalance = True
if not rebalance:
return
Finally, execute your trades. Always sell first to generate cash in the account and avoid margins.
# Sell shares first
for d, value in track_trades.items():
if value["units"] < 0:
self.sell(d, size=value["units"])
# Buy shares second
for d, value in track_trades.items():
if value["units"] > 0:
self.buy(d, size=value["units"])
Here is the all of the code for your reference.
import datetime
import backtrader as bt
class Strategy(bt.Strategy):
params = (
("buffer", 0.05),
("threshold", 0.025),
)
def log(self, txt, dt=None):
""" Logging function fot this strategy"""
dt = dt or self.data.datetime[0]
if isinstance(dt, float):
dt = bt.num2date(dt)
print("%s, %s" % (dt.date(), txt))
def print_signal(self):
self.log(
f"o {self.datas[0].open[0]:7.2f} "
f"h {self.datas[0].high[0]:7.2f} "
f"l {self.datas[0].low[0]:7.2f} "
f"c {self.datas[0].close[0]:7.2f} "
f"v {self.datas[0].volume[0]:7.0f} "
)
def notify_order(self, order):
""" Triggered upon changes to orders. """
# Suppress notification if it is just a submitted order.
if order.status == order.Submitted:
return
# Print out the date, security name, order number and status.
type = "Buy" if order.isbuy() else "Sell"
self.log(
f"{order.data._name:<6} Order: {order.ref:3d} "
f"Type: {type:<5}\tStatus"
f" {order.getstatusname():<8} \t"
f"Size: {order.created.size:9.4f} Price: {order.created.price:9.4f} "
f"Position: {self.getposition(order.data).size:5.2f}"
)
if order.status == order.Margin:
return
# Check if an order has been completed
if order.status in [order.Completed]:
self.log(
f"{order.data._name:<6} {('BUY' if order.isbuy() else 'SELL'):<5} "
# f"EXECUTED for: {dn} "
f"Price: {order.executed.price:6.2f} "
f"Cost: {order.executed.value:6.2f} "
f"Comm: {order.executed.comm:4.2f} "
f"Size: {order.created.size:9.4f} "
)
def notify_trade(self, trade):
"""Provides notification of closed trades."""
if trade.isclosed:
self.log(
"{} Closed: PnL Gross {}, Net {},".format(
trade.data._name,
round(trade.pnl, 2),
round(trade.pnlcomm, 1),
)
)
def next(self):
track_trades = dict()
total_value = self.broker.get_value() * (1 - self.p.buffer)
for d in self.datas:
track_trades[d] = dict()
value = self.broker.get_value(datas=[d])
allocation = value / total_value
units_to_trade = (d.target - allocation) * total_value / d.close[0]
track_trades[d]["units"] = units_to_trade
# Can check to make sure there is enough distance away from ideal to trade.
track_trades[d]["threshold"] = abs(d.target - allocation) > self.p.threshold
rebalance = False
for values in track_trades.values():
if values['threshold']:
rebalance = True
if not rebalance:
return
# Sell shares first
for d, value in track_trades.items():
if value["units"] < 0:
self.sell(d, size=value["units"])
# Buy shares second
for d, value in track_trades.items():
if value["units"] > 0:
self.buy(d, size=value["units"])
if __name__ == "__main__":
cerebro = bt.Cerebro()
tickers = {"FB": 0.25, "MSFT": 0.4, "TSLA": 0.35}
for ticker, target in tickers.items():
data = bt.feeds.YahooFinanceData(
dataname=ticker,
timeframe=bt.TimeFrame.Days,
fromdate=datetime.datetime(2019, 1, 1),
todate=datetime.datetime(2020, 12, 31),
reverse=False,
)
data.target = target
cerebro.adddata(data, name=ticker)
cerebro.addstrategy(Strategy)
# Execute
cerebro.run()
