StopTrail(Limit)ΒΆ

Release 1.9.35.116 adds the StopTrail and StopTrailLimit order execution types to the backtesting arsenal.

Note

This is only implemented in backtesting and there isn’t yet an implementation for live brokers

Note

Updated with release 1.9.36.116. Interactive Brokers support for StopTrail, StopTrailLimit and OCO.

  • OCO Specify always the 1st order in a group as parameter oco
  • StopTrailLimit: the broker simulation and the IB broker have the asme behavior. Specify: price as the initial stop trigger price (specify also trailamount) and then plimi as the initial limit price. The difference between the two will determine the limitoffset (the distance at which the limit price remains from the stop trigger price)

The usage pattern is fully integrated into the standard buy, sell and close market operation methods of the strategy instances. To notice:

  • Indicate which execution type is wished as in exectype=bt.Order.StopTrail
  • And whether the trailing price must be calculated with a fixed distance or with a percentage based distance
    • Fixed distance: trailamount=10
    • Percentage based distance: trailpercent=0.02 (i.e.: 2%)

If one has entered the market long by issuing a buy, this is what a sell with StopTrail and trailamount does:

  • If no price is specified, the latest close price is used
  • trailamount is substracted from the price to find the stop (or trigger) price
  • The next iteration of the broker checks if the trigger price has been reached
    • If Yes: the order is executed with a Market execution type approach
    • If No, the stop price is recalculated by using the latest close price and substracting the trailamount distance
      • If the new price goes up, it is updated
      • If the new price would go down (or not change at all), it is discarded

That is: the trailing stop price follows the price upwards, but remains fixed if the prices start falling, to potentially secure a profit.

If one had entered the market with a sell, then issuing a buy order with StopTrail simply does the opposite, i.e.: prices are followed downwards.

Some usage patterns

# For a StopTrail going downwards
# last price will be used as reference
self.buy(size=1, exectype=bt.Order.StopTrail, trailamount=0.25)
# or
self.buy(size=1, exectype=bt.Order.StopTrail, price=10.50, trailamount=0.25)

# For a StopTrail going upwards
# last price will be used as reference
self.sell(size=1, exectype=bt.Order.StopTrail, trailamount=0.25)
# or
self.sell(size=1, exectype=bt.Order.StopTrail, price=10.50, trailamount=0.25)

One can also specify trailpercent instead of trailamount and the distance to the price will be calculated as a percentage of the price

# For a StopTrail going downwards with 2% distance
# last price will be used as reference
self.buy(size=1, exectype=bt.Order.StopTrail, trailpercent=0.02)
# or
self.buy(size=1, exectype=bt.Order.StopTrail, price=10.50, trailpercent=0.0.02)

# For a StopTrail going upwards with 2% difference
# last price will be used as reference
self.sell(size=1, exectype=bt.Order.StopTrail, trailpercent=0.02)
# or
self.sell(size=1, exectype=bt.Order.StopTrail, price=10.50, trailpercent=0.02)

For a StopTrailLimit

  • The only difference is what happens when the trailing stop price is triggered.

  • In this case the order is executed as a Limit order (the same behavior a StopLimit order has, but in this case with a dynamic triggering price)

    Note

    one has to specify plimit=x.x to buy or sell, which will be the limit price

    Note

    the limit price is not changed dynamically like the stop/trigger price

An example is always worth a thousand words and hence the usual backtrader sample, which

  • Uses a moving average crossing up to enter the market long
  • Uses a trailing stop to exit the market

The execution with 50 points of fixed price distance

$ ./trail.py --plot --strat trailamount=50.0

Which produces the following chart

And the following output:

**************************************************
2005-02-14,3075.76,3025.76,3025.76
----------
2005-02-15,3086.95,3036.95,3036.95
2005-02-16,3068.55,3036.95,3018.55
2005-02-17,3067.34,3036.95,3017.34
2005-02-18,3072.04,3036.95,3022.04
2005-02-21,3063.64,3036.95,3013.64
...
...
**************************************************
2005-05-19,3051.79,3001.79,3001.79
----------
2005-05-20,3050.45,3001.79,3000.45
2005-05-23,3070.98,3020.98,3020.98
2005-05-24,3066.55,3020.98,3016.55
2005-05-25,3059.84,3020.98,3009.84
2005-05-26,3086.08,3036.08,3036.08
2005-05-27,3084.0,3036.08,3034.0
2005-05-30,3096.54,3046.54,3046.54
2005-05-31,3076.75,3046.54,3026.75
2005-06-01,3125.88,3075.88,3075.88
2005-06-02,3131.03,3081.03,3081.03
2005-06-03,3114.27,3081.03,3064.27
2005-06-06,3099.2,3081.03,3049.2
2005-06-07,3134.82,3084.82,3084.82
2005-06-08,3125.59,3084.82,3075.59
2005-06-09,3122.93,3084.82,3072.93
2005-06-10,3143.85,3093.85,3093.85
2005-06-13,3159.83,3109.83,3109.83
2005-06-14,3162.86,3112.86,3112.86
2005-06-15,3147.55,3112.86,3097.55
2005-06-16,3160.09,3112.86,3110.09
2005-06-17,3178.48,3128.48,3128.48
2005-06-20,3162.14,3128.48,3112.14
2005-06-21,3179.62,3129.62,3129.62
2005-06-22,3182.08,3132.08,3132.08
2005-06-23,3190.8,3140.8,3140.8
2005-06-24,3161.0,3140.8,3111.0
...
...
...
**************************************************
2006-12-19,4100.48,4050.48,4050.48
----------
2006-12-20,4118.54,4068.54,4068.54
2006-12-21,4112.1,4068.54,4062.1
2006-12-22,4073.5,4068.54,4023.5
2006-12-27,4134.86,4084.86,4084.86
2006-12-28,4130.66,4084.86,4080.66
2006-12-29,4119.94,4084.86,4069.94

Rather than waiting for the usual cross down pattern the system uses the trailing stop to exit the market. Let’s see the 1st operation for example

  • Closing price when entering long: 3075.76
  • System calculated trail stop price: 3025.76 (which is 50 units away)
  • Sample calculated trail stop price: 3025.76 (last price shown in each line)

After this first calculation:

  • The closing price goes up to 3086.95 and the stop price is adjusted to 3036.95
  • The following closing prices don’t exceed 3086.95 and the trigger price doesn’t change

The same pattern can be seen in the other 2 operations.

For the sake of comparison, an execution with just 30 points of fixed distance (just the chart)

$ ./trail.py --plot --strat trailamount=30.0

And the chart

Followed by one last execution with trailpercent=0.02

$ ./trail.py --plot --strat trailpercent=0.02

The corresponding chart.

The sample usage

$ ./trail.py --help
usage: trail.py [-h] [--data0 DATA0] [--fromdate FROMDATE] [--todate TODATE]
                [--cerebro kwargs] [--broker kwargs] [--sizer kwargs]
                [--strat kwargs] [--plot [kwargs]]

StopTrail Sample

optional arguments:
  -h, --help           show this help message and exit
  --data0 DATA0        Data to read in (default:
                       ../../datas/2005-2006-day-001.txt)
  --fromdate FROMDATE  Date[time] in YYYY-MM-DD[THH:MM:SS] format (default: )
  --todate TODATE      Date[time] in YYYY-MM-DD[THH:MM:SS] format (default: )
  --cerebro kwargs     kwargs in key=value format (default: )
  --broker kwargs      kwargs in key=value format (default: )
  --sizer kwargs       kwargs in key=value format (default: )
  --strat kwargs       kwargs in key=value format (default: )
  --plot [kwargs]      kwargs in key=value format (default: )

The sample code

from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

import argparse
import datetime

import backtrader as bt


class St(bt.Strategy):
    params = dict(
        ma=bt.ind.SMA,
        p1=10,
        p2=30,
        stoptype=bt.Order.StopTrail,
        trailamount=0.0,
        trailpercent=0.0,
    )

    def __init__(self):
        ma1, ma2 = self.p.ma(period=self.p.p1), self.p.ma(period=self.p.p2)
        self.crup = bt.ind.CrossUp(ma1, ma2)
        self.order = None

    def next(self):
        if not self.position:
            if self.crup:
                o = self.buy()
                self.order = None
                print('*' * 50)

        elif self.order is None:
            self.order = self.sell(exectype=self.p.stoptype,
                                   trailamount=self.p.trailamount,
                                   trailpercent=self.p.trailpercent)

            if self.p.trailamount:
                tcheck = self.data.close - self.p.trailamount
            else:
                tcheck = self.data.close * (1.0 - self.p.trailpercent)
            print(','.join(
                map(str, [self.datetime.date(), self.data.close[0],
                          self.order.created.price, tcheck])
                )
            )
            print('-' * 10)
        else:
            if self.p.trailamount:
                tcheck = self.data.close - self.p.trailamount
            else:
                tcheck = self.data.close * (1.0 - self.p.trailpercent)
            print(','.join(
                map(str, [self.datetime.date(), self.data.close[0],
                          self.order.created.price, tcheck])
                )
            )


def runstrat(args=None):
    args = parse_args(args)

    cerebro = bt.Cerebro()

    # Data feed kwargs
    kwargs = dict()

    # Parse from/to-date
    dtfmt, tmfmt = '%Y-%m-%d', 'T%H:%M:%S'
    for a, d in ((getattr(args, x), x) for x in ['fromdate', 'todate']):
        if a:
            strpfmt = dtfmt + tmfmt * ('T' in a)
            kwargs[d] = datetime.datetime.strptime(a, strpfmt)

    # Data feed
    data0 = bt.feeds.BacktraderCSVData(dataname=args.data0, **kwargs)
    cerebro.adddata(data0)

    # Broker
    cerebro.broker = bt.brokers.BackBroker(**eval('dict(' + args.broker + ')'))

    # Sizer
    cerebro.addsizer(bt.sizers.FixedSize, **eval('dict(' + args.sizer + ')'))

    # Strategy
    cerebro.addstrategy(St, **eval('dict(' + args.strat + ')'))

    # Execute
    cerebro.run(**eval('dict(' + args.cerebro + ')'))

    if args.plot:  # Plot if requested to
        cerebro.plot(**eval('dict(' + args.plot + ')'))


def parse_args(pargs=None):
    parser = argparse.ArgumentParser(
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
        description=(
            'StopTrail Sample'
        )
    )

    parser.add_argument('--data0', default='../../datas/2005-2006-day-001.txt',
                        required=False, help='Data to read in')

    # Defaults for dates
    parser.add_argument('--fromdate', required=False, default='',
                        help='Date[time] in YYYY-MM-DD[THH:MM:SS] format')

    parser.add_argument('--todate', required=False, default='',
                        help='Date[time] in YYYY-MM-DD[THH:MM:SS] format')

    parser.add_argument('--cerebro', required=False, default='',
                        metavar='kwargs', help='kwargs in key=value format')

    parser.add_argument('--broker', required=False, default='',
                        metavar='kwargs', help='kwargs in key=value format')

    parser.add_argument('--sizer', required=False, default='',
                        metavar='kwargs', help='kwargs in key=value format')

    parser.add_argument('--strat', required=False, default='',
                        metavar='kwargs', help='kwargs in key=value format')

    parser.add_argument('--plot', required=False, default='',
                        nargs='?', const='{}',
                        metavar='kwargs', help='kwargs in key=value format')

    return parser.parse_args(pargs)


if __name__ == '__main__':
    runstrat()