ataraxis-time

Provides a high-precision thread-safe timer and helper methods to work with date and time data.

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Detailed Description

This library uses the 'chrono' C++ library to access the fastest available system clock and use it to provide interval timing, delay, timeout, and polling functionality via a Python binding API. While the performance of the timer heavily depends on the particular system configuration and utilization, most modern CPUs should be capable of microsecond precision using this timer. Due to using a C-extension to provide interval and delay timing functionality, the library is thread- and process-safe and releases the GIL when using the appropriate delay command configuration. Additionally, the library offers a set of standalone helper functions for manipulating date and time data, including timestamp generation and parsing, time-unit conversion, rate-interval conversion, and timedelta interoperability.

Features

• Supports Windows, Linux, and macOS.
• Microsecond precision on modern CPUs (~ 3 GHz+) during delay and interval timing.
• Releases GIL during (non-blocking) delay timing even when using microsecond and nanosecond precision.
• Timeout guard class for activity-based and duration-based timeout tracking.
• Lap recording, human-readable elapsed time formatting, and periodic polling via an infinite generator.
• Frequency-to-interval and interval-to-frequency conversion helpers.
• Timestamp generation, conversion, and parsing with configurable precision levels.
• Interoperability with Python datetime.timedelta objects.
• Apache 2.0 License.

Table of Contents

• Dependencies
• Installation
• Usage
  • Precision Timer
  • Timeout
  • Date and Time Helper Functions
• API Documentation
• Developers
• Versioning
• Authors
• License
• Acknowledgments

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Dependencies

For users, all library dependencies are installed automatically by all supported installation methods. For developers, see the Developers section for information on installing additional development dependencies.

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Installation

Source

Note, installation from source is highly discouraged for anyone who is not an active project developer.

1. Download this repository to the local machine using the preferred method, such as git-cloning. Use one of the stable releases that include precompiled binary and source code distribution (sdist) wheels.
2. If the downloaded distribution is stored as a compressed archive, unpack it using the appropriate decompression tool.
3. cd to the root directory of the prepared project distribution.
4. Run pip install . to install the project and its dependencies.

pip

Use the following command to install the library and all of its dependencies via pip: pip install ataraxis-time

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Usage

Precision Timer

The timer API is intentionally minimalistic to simplify class adoption and usage. It is heavily inspired by the elapsedMillis library for Teensy and Arduino microcontrollers.

All timer class functionality is realized through a fast C-extension class wrapped into the PrecisionTimer class.

Initialization and Configuration

The timer takes the 'precision' to use as the only initialization argument. All instances of the timer class are thread- and process-safe and do not interfere with each other.

from ataraxis_time import PrecisionTimer, TimerPrecisions

# Currently, the timer supports 4 precisions: 'ns' (nanoseconds), 'us' (microseconds), 'ms' (milliseconds), and
# 's' (seconds). All precisions are defined in the TimerPrecisions enumeration.
timer = PrecisionTimer(TimerPrecisions.MICROSECOND)
print(f"Precision: {timer.precision}")

# The precision can be adjusted after initialization if needed. While not recommended, it is possible to provide the
# precision as a string instead of using the TimerPrecisions enumeration.
timer.set_precision('ms')  # Switches timer precision to milliseconds
print(f"Precision: {timer.precision}")

Interval Timing

Interval timing functionality is realized through two methods: reset() and the elapsed property. This functionality is identical to using perf_counter_ns() from the 'time' library. The main difference is that PrecisionTimer uses a slightly different interface (reset / elapsed) and automatically converts the output to the desired precision.

from ataraxis_time import PrecisionTimer
import time as tm

timer = PrecisionTimer('us')

# Interval timing example
timer.reset()  # Resets (re-bases) the timer
tm.sleep(1)  # Simulates work (for 1 second)
print(f'Work time: {timer.elapsed} us')

Delay

Delay timing functionality is the primary advantage of this library over the standard 'time' library. At the time of writing, the 'time' library can provide nanosecond-precise delays via a 'busywait' perf_counter_ns() function that does not release the GIL. Alternatively, it can release the GIL via the sleep() function, but it is only accurate up to millisecond precision. The PrecisionTimer class can delay for time-periods within microsecond precision, while releasing or holding the GIL.

import threading
import time
from ataraxis_time import PrecisionTimer

# Instantiates a global counter for the background thread
counter = 0
stop = False


def count_in_background():
    """Background thread that increments the global counter."""
    global counter
    while not stop:
        counter += 1


# Setup
timer = PrecisionTimer('us')

# Starts the background counter thread
thread = threading.Thread(target=count_in_background, daemon=True)
thread.start()
time.sleep(0.1)

# GIL-releasing microsecond delay:
print("block=False (releases GIL):")
counter = 0  # Resets the counter
timer.delay(100, block=False)  # 100us delay
non_blocking_count = counter
print(f"counter = {counter}")

# Non-GIL-releasing microsecond delay:
print("block=True (holds GIL):")
counter = 0  # Resets the counter
timer.delay(100, block=True)  # 100us delay
blocking_count = counter
print(f"counter = {counter}")

# Cleanup
stop = True

# With microsecond precisions, blocking runtime often results in the counter not being incremented at all.
if blocking_count == 0:
    blocking_count = 1
print(f"Difference: block=False allows ~{non_blocking_count/blocking_count:.0f}x more counting!")
thread.join()

Lap Timing

The lap() method records the current elapsed time, appends it to an internal list, and resets the timer. All recorded lap times are accessible through the laps property.

from ataraxis_time import PrecisionTimer
import time as tm

timer = PrecisionTimer('ms')

# Records three laps
for i in range(3):
    tm.sleep(0.1)  # Simulates work
    duration = timer.lap()
    print(f"Lap {i + 1}: {duration} ms")

# Retrieves all recorded laps as a tuple
print(f"All laps: {timer.laps}")

Formatted Elapsed Time

The format_elapsed() method returns the current elapsed time as a human-readable string, automatically selecting the most appropriate units.

from ataraxis_time import PrecisionTimer
import time as tm

timer = PrecisionTimer('us')
tm.sleep(2.5)  # Simulates work
print(f"Elapsed: {timer.format_elapsed()}")  # e.g. "2 s 500.117 ms"
print(f"Detailed: {timer.format_elapsed(max_fields=3)}")  # e.g. "2 s 500 ms 117.0 us"

Polling

The poll() method provides an infinite generator that yields an iteration count after each delay cycle. This is useful for periodic task execution.

from ataraxis_time import PrecisionTimer

timer = PrecisionTimer('ms')

# Polls every 100 ms, runs 10 iterations
for count in timer.poll(100):
    print(f"Iteration {count}")
    if count >= 10:
        break

Timeout

The Timeout class provides a timeout guard built on PrecisionTimer. It supports checking whether a specified duration has elapsed and offers activity-based reset (kick) and full reset with optional duration changes.

from ataraxis_time import Timeout
import time as tm

# Creates a 500 ms timeout
timeout = Timeout(duration=500, precision='ms')

# Checks timeout status
tm.sleep(0.1)
print(f"Expired: {timeout.expired}")  # False
print(f"Remaining: {timeout.remaining} ms")
print(f"Elapsed: {timeout.elapsed} ms")

# Resets the timeout timer without changing the duration (activity-based reset)
timeout.kick()

# Resets the timeout with a new duration
timeout.reset(duration=1000)

Date and Time Helper Functions

These are helper functions that are not directly part of the timer classes showcased above. Since these functions are not intended for realtime applications, they are implemented entirely in Python.

Convert Time

This helper function performs time-conversions, rounding to 3 decimal places, and works with time-scales from nanoseconds to days.

from ataraxis_time import convert_time, TimeUnits

# The conversion works for Python and NumPy scalars. Use the TimeUnits enumeration to specify input and
# output units. By default, the method returns the converted data as NumPy 64-bit floating scalars.
initial_time = 12
time_in_seconds = convert_time(time=initial_time, from_units=TimeUnits.DAY, to_units=TimeUnits.SECOND)
print(f"12 days is {time_in_seconds} seconds.")

# It is possible to provide the units directly, instead of using the TimeUnits enumeration. Also,
# it is possible to instruct the function to return Python floats.
initial_time = 5
time_in_minutes = convert_time(time=initial_time, from_units="s", to_units="m", as_float=True)
print(f"5 seconds is {time_in_minutes} minutes.")

Rate and Interval Conversion

The rate_to_interval() and interval_to_rate() functions convert between frequencies (Hz) and time intervals.

from ataraxis_time import rate_to_interval, interval_to_rate, TimeUnits

# Converts a 30 Hz frequency to a microsecond interval
interval_us = rate_to_interval(rate=30, to_units=TimeUnits.MICROSECOND)
print(f"30 Hz = {interval_us} us interval")

# Converts a 1000 us interval back to Hz
rate_hz = interval_to_rate(interval=1000, from_units=TimeUnits.MICROSECOND)
print(f"1000 us = {rate_hz} Hz")

Timedelta Interoperability

The to_timedelta() and from_timedelta() functions convert between numeric time values and Python datetime.timedelta objects.

from ataraxis_time import to_timedelta, from_timedelta, TimeUnits

# Converts 500 milliseconds to a timedelta
td = to_timedelta(time=500, from_units=TimeUnits.MILLISECOND)
print(f"500 ms as timedelta: {td}")

# Converts a timedelta back to microseconds
us_value = from_timedelta(timedelta_value=td, to_units=TimeUnits.MICROSECOND)
print(f"Timedelta as microseconds: {us_value}")

Timestamps

Timestamp methods generate and work with microsecond-precise UTC timestamps. The generated timestamp can be returned as and freely converted between three supported formats: string, bytes array, and an integer number of microseconds elapsed since the UTC epoch onset. The precision parameter controls how much detail is included in the output.

from ataraxis_time import get_timestamp, convert_timestamp, TimestampFormats, TimestampPrecisions

# Gets the current date and time as a timestamp. The timestamp is precise up to microseconds by default.
# Use TimestampFormats to specify the desired format.
dt = get_timestamp(time_separator='-', output_format=TimestampFormats.STRING)
print(f"Current timestamp: {dt}.")

# Uses the precision parameter to control the detail level of the output.
dt_day = get_timestamp(output_format=TimestampFormats.STRING, precision=TimestampPrecisions.DAY)
print(f"Day-precision timestamp: {dt_day}.")

# The function also supports giving the timestamp as a serialized array of bytes. This is helpful when it is used as
# part of a serialized communication protocol.
bytes_dt = get_timestamp(output_format=TimestampFormats.BYTES)
print(f"Byte-serialized current timestamp value: {bytes_dt}.")

# Use the convert_timestamp() function to convert the timestamp to a different format. It supports cross-converting
# all timestamp formats stored in the TimestampFormats enumeration.
integer_dt = convert_timestamp(timestamp=bytes_dt, output_format=TimestampFormats.INTEGER)
string_dt = convert_timestamp(timestamp=integer_dt, output_format=TimestampFormats.STRING)
print(
    f"The timestamp can be read as a string: {string_dt}. It can also be read as the number of microseconds elapsed "
    f"since UTC epoch onset: {integer_dt}."
)

Parse Timestamp

The parse_timestamp() function parses arbitrary datetime strings using strptime-compatible format strings and returns them as timestamps in any supported format.

from ataraxis_time import parse_timestamp, TimestampFormats

# Parses a datetime string into a microsecond integer timestamp
us_timestamp = parse_timestamp(
    date_string="2024-03-15 14:30:00",
    format_string="%Y-%m-%d %H:%M:%S",
    output_format=TimestampFormats.INTEGER,
)
print(f"Parsed timestamp: {us_timestamp}")

# Parses into a string timestamp with day precision
day_timestamp = parse_timestamp(
    date_string="March 15, 2024",
    format_string="%B %d, %Y",
    output_format=TimestampFormats.STRING,
    precision="day",
)
print(f"Day-precision parsed timestamp: {day_timestamp}")

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API Documentation

See the API documentation for the detailed description of the methods and classes exposed by components of this library. The documentation also covers the C++ source code and the axt-benchmark CLI command.

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Developers

This section provides installation, dependency, and build-system instructions for the developers that want to modify the source code of this library.

Installing the Project

Note, this installation method requires mamba version 2.3.2 or above. Currently, all Sun lab automation pipelines require that mamba is installed through the miniforge3 installer.

1. Download this repository to the local machine using the preferred method, such as git-cloning.
2. If the downloaded distribution is stored as a compressed archive, unpack it using the appropriate decompression tool.
3. cd to the root directory of the prepared project distribution.
4. Install the core Sun lab development dependencies into the base mamba environment via the mamba install tox uv tox-uv command.
5. Use the tox -e create command to create the project-specific development environment followed by tox -e install command to install the project into that environment as a library.

Additional Dependencies

In addition to installing the project and all user dependencies, install the following dependencies:

1. Python distributions, one for each version supported by the developed project. Currently, this library supports the three latest stable versions. It is recommended to use a tool like pyenv to install and manage the required versions.
2. Doxygen, if you want to generate C++ code documentation.
3. An appropriate build tool or Docker, if you intend to build binary wheels via cibuildwheel. See the link for information on which dependencies to install for each development platform.

Development Automation

This project uses tox for development automation. The following tox environments are available:

Environment	Description
lint	Runs ruff formatting, ruff linting, and mypy type checking
stubs	Generates py.typed marker and .pyi stub files
{py312,...}-test	Runs the test suite via pytest for each supported Python
coverage	Aggregates test coverage into an HTML report
docs	Builds the API documentation via Sphinx
build	Builds sdist and wheel distributions
upload	Uploads distributions to PyPI via twine
install	Builds and installs the project into its mamba environment
uninstall	Uninstalls the project from its mamba environment
create	Creates the project's mamba development environment
remove	Removes the project's mamba development environment
provision	Recreates the mamba environment from scratch
export	Exports the mamba environment as .yml and spec.txt files
import	Creates or updates the mamba environment from a .yml file

Run any environment using tox -e ENVIRONMENT. For example, tox -e lint.

Note, all pull requests for this project have to successfully complete the tox task before being merged. To expedite the task's runtime, use the tox --parallel command to run some tasks in parallel.

Automation Troubleshooting

Many packages used in tox automation pipelines (uv, mypy, ruff) and tox itself may experience runtime failures. In most cases, this is related to their caching behavior. If an unintelligible error is encountered with any of the automation components, deleting the corresponding cache directories (.tox, .ruff_cache, .mypy_cache, etc.) manually or via a CLI command typically resolves the issue.

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Versioning

This project uses semantic versioning. See the tags on this repository for the available project releases.

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Authors

• Ivan Kondratyev (Inkaros)

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License

This project is licensed under the Apache 2.0 License: see the LICENSE file for details.

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Acknowledgments

• All Sun lab members for providing the inspiration and comments during the development of this library.
• elapsedMillis project for providing the inspiration for the API and the functionality of the timer class.
• nanobind project for providing a fast and convenient way of binding C++ code to Python projects.
• The creators of all other dependencies and projects listed in the pyproject.toml file.