PyFacts/check.py

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import datetime
import math
import random
# import time
from typing import List
from dateutil.relativedelta import relativedelta
import pyfacts as pft
def create_prices(s0: float, mu: float, sigma: float, num_prices: int) -> list:
"""Generates a price following a geometric brownian motion process based on the input of the arguments.
Since this function is used only to generate data for tests, the seed is fixed as 1234.
Many of the tests rely on exact values generated using this seed.
If the seed is changed, those tests will fail.
Parameters:
------------
s0: float
Asset inital price.
mu: float
Interest rate expressed annual terms.
sigma: float
Volatility expressed annual terms.
num_prices: int
number of prices to generate
Returns:
--------
Returns a list of values generated using GBM algorithm
"""
random.seed(1234) # WARNING! Changing the seed will cause most tests to fail
all_values = []
for _ in range(num_prices):
s0 *= math.exp(
(mu - 0.5 * sigma**2) * (1.0 / 365.0) + sigma * math.sqrt(1.0 / 365.0) * random.gauss(mu=0, sigma=1)
)
all_values.append(round(s0, 2))
return all_values
def sample_data_generator(
frequency: pft.Frequency,
num: int = 1000,
skip_weekends: bool = False,
mu: float = 0.1,
sigma: float = 0.05,
eomonth: bool = False,
) -> List[tuple]:
"""Creates TimeSeries data
Parameters:
-----------
frequency: Frequency
The frequency of the time series data to be generated.
num: int
Number of date: value pairs to be generated.
skip_weekends: bool
Whether weekends (saturday, sunday) should be skipped.
Gets used only if the frequency is daily.
mu: float
Mean return for the values.
sigma: float
standard deviation of the values.
Returns:
--------
Returns a TimeSeries object
"""
start_date = datetime.datetime(2017, 1, 1)
timedelta_dict = {
frequency.freq_type: int(
frequency.value * num * (7 / 5 if frequency == pft.AllFrequencies.D and skip_weekends else 1)
)
}
end_date = start_date + relativedelta(**timedelta_dict)
dates = pft.create_date_series(start_date, end_date, frequency.symbol, skip_weekends=skip_weekends, eomonth=eomonth)
values = create_prices(1000, mu, sigma, num)
ts = list(zip(dates, values))
return ts
market_data = sample_data_generator(num=3600, frequency=pft.AllFrequencies.D, skip_weekends=False)
mts = pft.TimeSeries(market_data, "D")
print(mts)
# print("Datediff=", (mts.end_date - mts.start_date).days)
# stock_data = sample_data_generator(num=3600, frequency=pft.AllFrequencies.D, skip_weekends=False, mu=0.12, sigma=0.15)
# sts = pft.TimeSeries(stock_data, "D")
# print(sts)
# start = time.time()
# alpha = pft.jensens_alpha(
# asset_data=sts, market_data=mts, risk_free_rate=0.052, return_period_unit="months", return_period_value=1
# )
# print(alpha)
# print("Alpha calculation took", time.time() - start, "seconds")
# print("Correlation=", pft.correlation(sts, mts))
rr = mts.calculate_rolling_returns(frequency="D")
print(117, rr[rr.values < 0.1])