zulip/analytics/lib/fixtures.py

63 lines
3.1 KiB
Python

from analytics.lib.counts import CountStat
from math import sqrt
from random import gauss, random, seed
from typing import List
def generate_time_series_data(days=100, business_hours_base=10, non_business_hours_base=10,
growth=1, autocorrelation=0, spikiness=1, holiday_rate=0,
frequency=CountStat.DAY, partial_sum=False, random_seed=26):
# type: (int, float, float, float, float, float, float, str, bool, int) -> List[int]
"""
Generate semi-realistic looking time series data for testing analytics graphs.
days -- Number of days of data. Is the number of data points generated if
frequency is CountStat.DAY.
business_hours_base -- Average value during a business hour (or day) at beginning of
time series, if frequency is CountStat.HOUR (CountStat.DAY, respectively).
non_business_hours_base -- The above, for non-business hours/days.
growth -- Ratio between average values at end of time series and beginning of time series.
autocorrelation -- Makes neighboring data points look more like each other. At 0 each
point is unaffected by the previous point, and at 1 each point is a deterministic
function of the previous point.
spikiness -- 0 means no randomness (other than holiday_rate), higher values increase
the variance.
holiday_rate -- Fraction of days randomly set to 0, largely for testing how we handle 0s.
frequency -- Should be CountStat.HOUR or CountStat.DAY.
partial_sum -- If True, return partial sum of the series.
random_seed -- Seed for random number generator.
"""
if frequency == CountStat.HOUR:
length = days*24
seasonality = [non_business_hours_base] * 24 * 7
for day in range(5):
for hour in range(8):
seasonality[24*day + hour] = business_hours_base
holidays = []
for i in range(days):
holidays.extend([random() < holiday_rate] * 24)
elif frequency == CountStat.DAY:
length = days
seasonality = [8*business_hours_base + 16*non_business_hours_base] * 5 + \
[24*non_business_hours_base] * 2
holidays = [random() < holiday_rate for i in range(days)]
else:
raise AssertionError("Unknown frequency: %s" % (frequency,))
if length < 2:
raise AssertionError("Must be generating at least 2 data points. "
"Currently generating %s" % (length,))
growth_base = growth ** (1. / (length-1))
values_no_noise = [seasonality[i % len(seasonality)] * (growth_base**i) for i in range(length)]
seed(random_seed)
noise_scalars = [gauss(0, 1)]
for i in range(1, length):
noise_scalars.append(noise_scalars[-1]*autocorrelation + gauss(0, 1)*(1-autocorrelation))
values = [0 if holiday else int(v + sqrt(v)*noise_scalar*spikiness)
for v, noise_scalar, holiday in zip(values_no_noise, noise_scalars, holidays)]
if partial_sum:
for i in range(1, length):
values[i] = values[i-1] + values[i]
return [max(v, 0) for v in values]