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quantconnect--lean/Algorithm.Framework/Alphas/PearsonCorrelationPairsTradingAlphaModel.py
2019-04-03 21:55:43 -03:00

117 lines
4.8 KiB
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 Alphas.BasePairsTradingAlphaModel import BasePairsTradingAlphaModel
from datetime import timedelta
from scipy.stats import pearsonr
import numpy as np
import pandas as pd
class PearsonCorrelationPairsTradingAlphaModel(BasePairsTradingAlphaModel):
''' This alpha model is designed to rank every pair combination by its pearson correlation
and trade the pair with the hightest correlation
This model generates alternating long ratio/short ratio insights emitted as a group'''
def __init__(self, lookback = 15,
resolution = Resolution.Minute,
threshold = 1,
minimumCorrelation = .5):
'''Initializes a new instance of the PearsonCorrelationPairsTradingAlphaModel class
Args:
lookback: lookback period of the analysis
resolution: analysis resolution
threshold: The percent [0, 100] deviation of the ratio from the mean before emitting an insight
minimumCorrelation: The minimum correlation to consider a tradable pair'''
super().__init__(lookback, resolution, threshold)
self.lookback = lookback
self.resolution = resolution
self.minimumCorrelation = minimumCorrelation
self.best_pair = ()
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 security in changes.AddedSecurities:
self.Securities.append(security)
for security in changes.RemovedSecurities:
if security in self.Securities:
self.Securities.remove(security)
symbols = [ x.Symbol for x in self.Securities ]
history = algorithm.History(symbols, self.lookback, self.resolution).close.unstack(level=0)
if not history.empty:
df = self.get_price_dataframe(history)
stop = len(df.columns)
corr = dict()
for i in range(0, stop):
for j in range(i+1, stop):
if (j, i) not in corr:
corr[(i, j)] = pearsonr(df.iloc[:,i], df.iloc[:,j])[0]
corr = sorted(corr.items(), key = lambda kv: kv[1])
if corr[-1][1] >= self.minimumCorrelation:
self.best_pair = (symbols[corr[-1][0][0]], symbols[corr[-1][0][1]])
super().OnSecuritiesChanged(algorithm, changes)
def HasPassedTest(self, algorithm, asset1, asset2):
'''Check whether the assets pass a pairs trading test
Args:
algorithm: The algorithm instance that experienced the change in securities
asset1: The first asset's symbol in the pair
asset2: The second asset's symbol in the pair
Returns:
True if the statistical test for the pair is successful'''
return self.best_pair is not None and self.best_pair == (asset1, asset2)
def get_price_dataframe(self, df):
timezones = { x.Symbol.Value: x.Exchange.TimeZone for x in self.Securities }
# Use log prices
df = np.log(df)
is_single_timeZone = len(set(timezones.values())) == 1
if not is_single_timeZone:
series_dict = dict()
for column in df:
# Change the dataframe index from data time to UTC time
to_utc = lambda x: Extensions.ConvertToUtc(x, timezones[column])
if self.resolution == Resolution.Daily:
to_utc = lambda x: Extensions.ConvertToUtc(x, timezones[column]).date()
data = df[[column]]
data.index = data.index.map(to_utc)
series_dict[column] = data[column]
df = pd.DataFrame(series_dict).dropna()
return (df - df.shift(1)).dropna()