Simple script to calculate the error of polling multiple sample rates with Python `time.sleep`

two_timing.py

import time
import numpy as np

fs_list = [120.0, 2.0]
dt_list = [1/fs for fs in fs_list]
prevt_list = [time.time(), ] * len(fs_list)
sample_times = [list() for fs in fs_list]

timeout_seconds = 10
sleep_seconds = min(dt_list) * 0.1

tstart = time.time()
while True:
    tnow = time.time()
    # this could be more efficient by removing the for loop and using
    # numpy for element-wise operations on an array instead of a list
    for cix in range(len(fs_list)):
        if tnow - prevt_list[cix] > dt_list[cix]:
            # FIXME: do something to trigger sampling on channel 'cix'

            # update timing parameter
            prevt_list[cix] += dt_list[cix]
            sample_times[cix].append(tnow)
        # end per channel timing check since that channel's last sample

    if tnow - tstart > timeout_seconds:
        break

    time.sleep(sleep_seconds)
# end while True

print("two_timing.py : fs_list = {}".format(fs_list))
print("two_timing.py : dt_list = {}".format(dt_list))
print("two_timing.py : sleep_seconds = {}".format(sleep_seconds))
for cix, fs in enumerate(fs_list):
    dts = np.diff(sample_times[cix])
    print(" -> Channel = {}".format(cix))
    print(" ...... expected       dt = {}".format(dt_list[cix]))
    print(" ...... mean of        dt = {}".format(np.mean(dts)))
    print(" ...... std  of        dt = {}".format(np.std(dts)))
    print(" ...... std / mean of  dt = {}".format(np.std(dts) / np.mean(dts)))