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quantconnect--lean/Algorithm.Framework/Alphas/PairsTradingAlphaModel.py
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2018-04-25 13:45:13 +01:00

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Python

# QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
# Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from clr import AddReference
AddReference("QuantConnect.Common")
AddReference("QuantConnect.Algorithm.Framework")
AddReference("QuantConnect.Indicators")
from QuantConnect import *
from QuantConnect.Indicators import *
from QuantConnect.Algorithm.Framework.Alphas import *
from datetime import timedelta
from enum import Enum
class PairsTradingAlphaModel:
'''This alpha model is designed to work against a single, predefined pair.
This model generates alternating long ratio/short ratio insights emitted as a group'''
class State(Enum):
ShortRatio = -1
FlatRatio = 0
LongRatio = 1
def __init__(self, asset1, asset2, threshold = 1):
''' Initializes a new instance of the PairsTradingAlphaModel class
Args:
asset1: The first asset's symbol in the pair
asset2: The second asset's symbol in the pair
threshold: The percent [0, 100] deviation of the ratio from the mean before emitting an insight'''
self.asset1 = asset1
self.asset2 = asset2
self.threshold = threshold
self.state = self.State.FlatRatio
self.asset1Price = None
self.asset2Price = None
self.ratio = None
self.mean = None
self.upperThreshold = None;
self.lowerThreshold = None;
self.Name = '{}({},{},{})'.format(self.__class__.__name__, asset1, asset2, Extensions.Normalize(threshold))
def Update(self, algorithm, data):
''' Updates this alpha model with the latest data from the algorithm.
This is called each time the algorithm receives data for subscribed securities
Args:
algorithm: The algorithm instance
data: The new data available
Returns:
The new insights generated'''
if self.mean is None or not self.mean.IsReady:
return []
# don't re-emit the same direction
if self.state is not self.State.LongRatio and self.ratio > self.upperThreshold:
self.state = self.State.LongRatio
# asset1/asset2 is more than 2 std away from mean, short asset1, long asset2
shortAsset1 = Insight.Price(self.asset1, timedelta(minutes = 15), InsightDirection.Down)
longAsset2 = Insight.Price(self.asset2, timedelta(minutes = 15), InsightDirection.Up)
# creates a group id and set the GroupId property on each insight object
Insight.Group(shortAsset1, longAsset2)
return [shortAsset1, longAsset2]
# don't re-emit the same direction
if self.state is not self.State.ShortRatio and self.ratio < self.lowerThreshold:
self.state = self.State.ShortRatio
# asset1/asset2 is less than 2 std away from mean, long asset1, short asset2
longAsset1 = Insight.Price(self.asset1, timedelta(minutes = 15), InsightDirection.Up)
shortAsset2 = Insight.Price(self.asset2, timedelta(minutes = 15), InsightDirection.Down)
# creates a group id and set the GroupId property on each insight object
Insight.Group(longAsset1, shortAsset2)
return [longAsset1, shortAsset2]
return []
def OnSecuritiesChanged(self, algorithm, changes):
'''Event fired each time the we add/remove securities from the data feed.
Args:
algorithm: The algorithm instance that experienced the change in securities
changes: The security additions and removals from the algorithm'''
for added in changes.AddedSecurities:
# this model is limitted to looking at a single pair of assets
if added.Symbol != self.asset1 and added.Symbol != self.asset2:
continue
if added.Symbol == self.asset1:
self.asset1Price = algorithm.Identity(added.Symbol)
else:
self.asset2Price = algorithm.Identity(added.Symbol)
if self.ratio is None:
# initialize indicators dependent on both assets
if self.asset1Price is not None and self.asset2Price is not None:
self.ratio = IndicatorExtensions.Over(self.asset1Price, self.asset2Price)
self.mean = IndicatorExtensions.Of(ExponentialMovingAverage(500), self.ratio)
upper = ConstantIndicator[IndicatorDataPoint]("ct", 1 + self.threshold / 100)
self.upperThreshold = IndicatorExtensions.Times(self.mean, upper)
lower = ConstantIndicator[IndicatorDataPoint]("ct", 1 - self.threshold / 100)
self.lowerThreshold = IndicatorExtensions.Times(self.mean, lower)