Metadata-Version: 2.1
Name: oclock
Version: 1.2.2
Summary: Tools for timed, no-drift loops of constant duration, and other misc. timing tools (GUI countdown, context managers etc.)
Home-page: https://github.com/ovinc/oclock
Author: Olivier Vincent
Author-email: ovinc.py@gmail.com
License: BSD 3-Clause License
Description: # About
        
        **oclock** is a Python 3 package. Its main goal is to provide a simple way to create timed loops with constant time intervals and no drift. It also provides various other timing tools and a GUI time.
        
        ### Timed loops
        
        No drift, timed loops are based on the `Timer` class,
        - either using the `checkpt()` method at a location in a for/while loop acting as a reference point to maintain constant duration from one loop to the next,
        - or using the `@loop` or `@interactiveloop` decorators that use `Timer` and `checkpt()` in the background.
        
        The timing (interval) and execution (pause/stop etc.) can be modified in real time thanks to cancellable sleeping times.
        
        ### Other tools
        
        - `Countdown`: a class that starts a GUI countdown timer.
        - `parse_time()` function: returns a `datetime.timedelta` from a time string (e.g. `':2:25'`).
        - `measure_time()` and `measure_duration()` functions: are context managers for measuring time and execution times / time uncertainty of encapsulated commands.
        - Note that the `Timer` class can also be used as a regular chronometer with its methods `pause()`, `resume()`, `stop()` etc.
        
        # Quick start
        
        ## Install
        
        ```bash
        pip install oclock
        ```
        
        ## Timed Loops
        
        The `Timer` class is mostly designed to create loops of constant duration without drift, while allowing immediate modification/cancellation (sleep time interruption) in threaded environments. It can also be used as a regular chronometer.
        
        Below are some peudo-code quick-start examples. For complete, working examples, see:
        - *Examples.ipynb* notebook (https://github.com/ovinc/oclock/blob/master/Example.ipynb)
        - *example.py* script (https://github.com/ovinc/oclock/blob/master/example.py)
        
        
        ### Constant-duration loops
        
        The most basic use of the `Timer()` class in Python code to create a loop of constant duration is:
        ```python
        from oclock import Timer
        timer = Timer(interval=2)  # Loops will be of total duration 2 seconds
        while condition:
            my_function()  # can be of any duration between 0 and 2 seconds
            timer.checkpt()
        ```
        The `checkpt()` method waits the adequate amount of time to make the loop of constant duration, without drift (using a target regularly spaced in time); `condition` can include timer methods and attributes, e.g. `timer.elapsed_time < max_time`.
        
        Note that if *my_function()* takes longer to execute than the required time interval, the Timer class does not try to compensate the extra time by making the next loop shorter. It just aims at making the total duration of the next loop be the requested interval again (see *Behavior when interval is exceeded* section below).
        
        The same behavior can be achieved using the `@loop` decorator:
        ```python
        from oclock import loop
        timer = Timer(interval=2)  # Loops will be of total duration 2 seconds
        @loop(timer)
        def my_function():
            ...
        ```
        Then, calling `my_function()` will execute the contents of the function in a repeated manner.
        
        The `@loop` execution exits automatically if the timer is stopped.
        Thus, It is useful to include a condition in `my_function` to exit the loop when needed, e.g.
        ```python
        if timer.elapsed_time > t_max:
            timer.stop()
        ```
        
        ### Interactive modification/cancellation
        
        The timer is also modifiable (change time interval) and cancellable in real time (i.e. even when the timer is in a `checkpt()` waiting phase). To do so, it must be accessed by another thread that runs concurrently. For example:
        
        ```python
        from oclock import Timer
        from threading import Thread
        
        def user_input(timer):
            """Threaded command line input to change time interval or exit timer."""
            while not timer.is_stopped:
                a = input()
                try:
                    dt = float(a)
                except ValueError:  # immediately cancel timer & exit all loops/threads
                    timer.stop()
                else:               # immediately change interval to input value
                    timer.interval = dt
        
        timer = Timer(interval=2)
        Thread(target=user_input, args=(exit_event, timer)).start()
        
        while not timer.is_stopped:
            my_function()
            timer.checkpt()
        ```
        During operation, the `Timer` object can be paused, resumed, stopped and reset using the corresponding `Timer` methods (see *Regular Timer* paragraph below). The *oclock* module also provides a simple command line interface to create a timed loop for a function and interact with it dynamically using the `@interactiveloop` decorator:
        ```python
        from oclock import interactiveloop
        @interactiveloop(interval=2)
        def my_function():
            ...
        ```
        Now when `my_function()` is called, an interactive CLI thread starts at the same time where the user can pause/resume/reset/stop the timer in real time, change its interval, and print timing information.
        
        ### Regular Timer
        
        Although not its main purpose, the `Timer` class can be used as a regular chronometer with the following methods (no need to be in a threaded environment, although the methods below whould work and be cancellable in a threaded environment):
        
        ```python
        from oclock import Timer
        
        # The timer starts counting time immediately upon instantiation.
        timer = Timer()
        
        # Temporarily pause, then resume timer
        timer.pause()
        timer.resume()
        
        # Stop and restart timer completely
        timer.stop()
        timer.reset()  # note: can be called without calling stop() first
        
        # At any time, the elapsed time and total pause duration can be accessed with
        timer.elapsed_time
        timer.pause_time
        timer.total_time  # sum of the two other times
        ```
        
        **Important Note**: Do not use the `checkpt()` method after a `pause()` call if not in a threaded environment, this will cause the program to be in a perpetual waiting state. In a threaded environment, call `resume()` to unpause.
        
        ### Details
        
        See *Timer Class details* section below for all methods, properties and attributes and the *Development* section below for accuracy information.
        
        ## Countdown GUI
        
        A simple graphical countdown timer based on the `Timer` class. It can be used either as a python main program from a shell, or as a function in Python code or console.
        
        ![](https://raw.githubusercontent.com/ovinc/oclock/master/media/countdown.gif)
        
        From a terminal:
        ```bash
        python -m oclock 1:45:00   # start timer of duration 1 hour 45 minutes
        python -m oclock 1:45:     # exactly the same as above
        python -m oclock 00:02:00  # start 2-minute timer
        python -m oclock :2:       # exactly the same as above
        python -m oclock 00:00:05  # start 5-second timer
        python -m oclock ::5       # exactly the same as above
        ```
        
        In python:
        ```python
        from oclock import Countdown
        Countdown('1:45:')         # start timer of duration 1 hour 45 minutes
        ```
        (the inputs are of the same format as from the terminal, see above).
        
        When countdown is finished, 'Done' is displayed for 5 seconds in the GUI while the console displays *Countdown finished* and emits a sound. Then the time passed since the end of countdown is displayed as a negative value in red. The program stops when the GUI window is closed.
        
        ## Parse time function
        
        The `parse_time()` function is used in the argument parsing of the countdown GUI from a terminal (see above). It transforms a string in the form `'h:m:s'` into a `datetime.timedelta` object. Inputs of the form e.g. `'::5'` or `:2:`, `'3:30:'` are acceptable for 5 seconds, 2 minutes, and 3.5 hours, respectively.
        ```python
        >>> parse_time(':2:30')
        datetime.timedelta(seconds=150)
        ```
        
        ## Context managers to record timing of commands
        
        The `measure_time()` function is a context manager that saves the timing info of the encapsulated commands. This can be e.g. used in scientific experiments to get the time and time uncertainty associated with a measurement.
        ```python
        from oclock import measure_time, measure_duration
        
        # ----------------------------------------------------------------------------
        # Examples where one just wants to get timing info ---------------------------
        # ----------------------------------------------------------------------------
        
        with measure_time() as timing:
            my_function()
        print(timing)
        
        # Out: {'time (unix)': 1604780958.0705943, 'dt (s)': 0.6218999624252319}
        
        # (dt (s) is half the total duration. To get the total duration instead, do:)
        
        with measure_duration() as duration:
            my_function()
        print(duration)
        
        # Out: {'duration (s)': 1.1689763555421325}
        
        # ----------------------------------------------------------------------------
        # Example where the timing info is directly added to a data dictionary -------
        # ----------------------------------------------------------------------------
        
        with measure_time() as data:
            measurement = my_function()  # returns e.g. 3.618
            data['measurement'] = measurement
        print(data)
        
        # Out: {'measurement': 3.618,
        #       'time (unix)': 1604780958.0705943,
        #       'dt (s)': 0.6218999624252319}
        ```
        
        
        # Timer Class details
        
        ## Instantiation
        
        ```python
        from oclock import Timer
        timer = Timer(interval=1, name='Timer', warnings=False)
        ```
        
        Parameters:
        - `interval` (float): timer interval in seconds
        - `name` (str): optional name for description purposes (repr and warnings)
        - `warnings` (bool): If True, prints warning when time interval exceeded
        
        ## Methods
        
        ```python
        timer.checkpt()  # Reference point for constant-duration loops, see above
        
        timer.pause()    # Immediately pause timer and put checkpt() in waiting phase
        timer.resume()   # Restart the elapsed time counter and unlock checkpt()
        
        timer.stop()     # Stop counting time and exit checkpt()
        timer.reset()    # Stop and restart timer immediately
        ```
        
        ## Properties (settable)
        
        ```python
        timer.interval       # get interval (in s)
        timer.interval += 1  # increase interval by 1 second
        timer.interval = 10  # set interval to 10 seconds.
        
        timer.warnings          # get current status of warnings
        timer.warnings = True   # activate warnings if time between checkpts too short
        
        timer.name                      # optional name (for repr and warnings)
        timer.name = 'Countdown timer'  # (can also be set during instantiation)
        ```
        
        ## Attributes (read-only)
        
        ```python
        # Most useful attributes
        timer.elapsed_time  # Time in seconds since init or last reset
        timer.pause_time    # total time (in s) the timer has been paused.
        timer.total_time    # Sum of the last two
        ```
        
        ## Background attributes and methods
        (mostly for development)
        ```python
        timer.now()                 # Reference time used by all methods
        timer.start_time            # Ref. time corresponding to start/reset of timer
        timer.next_checkpt_release  # Ref. time at which next checkpt waittime is over
        timer.interval_exceeded     # (bool) True if loop contents take longer to execute than requested interval
        ```
        
        ## Notes
        
        - As mentioned previously, methods (and interval setting) take effect immediately, even if the timer is in a waiting phase.
        
        - After calling `pause()`, the `checkpt()` command blocks until `resume()` is called, however in the current version after `stop()` the `checkpt()` becomes non-blocking (equivalent to a `pass`), so that all following lines will be executed immediately and without any waiting time (i.e. as fast as possible if within a loop), until `timer.reset()` is called again. This means that it is useful to pin the condition of the loop to the stopping of the timer (see examples).
        
        
        ## Accuracy test
        
        See *performance.py* file of the module for functions to test the accuracy of the timer. In particular:
        ```python
        from oclock.performance import performance_test
        performance_test(dt=0.1, nloops=1000, fmax=0.99)
        ```
        tests the timing on 1000 loops of requested duration 0.1 second (100ms), using within the loop a function sleeping for a random amount of time between 0 and 0.99*dt (use `plot=True` option to see the results on a *matplotlib* graph, and `warnings=True` to have a printed warning when the execution time of the nested commands exceed the target duration of the loop).
        
        Below are some quick preliminary results on timing accuracy in an Unix Environment (MacOS) and Windows, using `nloops=1000`, `fmax=0.5` for various values of `dt`. As can be seen, The Timer seems to perform well in Unix environments even down to millisecond intervals (1000fps), while it starts having difficulties below 40 ms intervals in Windows (25 fps).
        
        ### Unix (MacOS)
        
        |         Requested `dt` (ms)        |  1000  | 100 (*) |   40    | 10 (**) |    1    |
        |:----------------------------------:|:------:|:-------:|:-------:|:-------:|:-------:|
        | average `dt` - requested `dt` (ms) | 0.0012 | 0.00012 | 0.00016 | 0.00005 | 0.00023 |
        | standard deviation in `dt` (ms)    | 0.48   | 0.36    |   0.31  |  0.23   | 0.08    |
        
        (*) corresponding graph:
        
        ![](https://raw.githubusercontent.com/ovinc/oclock/master/media/img/timer_macos_100ms.png)
        
        (**) corresponding graph:
        
        ![](https://raw.githubusercontent.com/ovinc/oclock/master/media/img/timer_macos_10ms.png)
        
        
        ### Windows
        
        |         Requested `dt` (ms)        | 1000  | 100 (*) |   40    | 10 (**) |  1  |
        |:----------------------------------:|:-----:|:-------:|:-------:|:-------:|:---:|
        | average `dt` - requested `dt` (ms) | 0.014 | 0.0015  | 0.0013  |  1.2    | 1.1 |
        | standard deviation in `dt` (ms)    | 7.0   | 7.1     |  7.0    |  5.6    | 1.9 |
        
        
        (*) corresponding graph:
        
        ![](https://raw.githubusercontent.com/ovinc/oclock/master/media/img/timer_windows_100ms.png)
        
        (**) Due to the large time fluctuations in Windows at this timescale, the use of the Timer is not really relevant anymore at theses interval values and lower. Work is under way to improve accuracy.
        
        ## Behavior when interval is exceeded
        
        As explained above, it the contents of the loop take longer to execute than the requested time interval, the Timer simply moves on to the next loop but does not try to compensate for the extra time by making the next loop shorter:
        
        ![](https://raw.githubusercontent.com/ovinc/oclock/master/media/img/timer_interval_exceeded.png)
        
        
        
        # Development
        
        Install the package by cloning the GitHub repo (https://github.com/ovinc/oclock.git) and install in editable mode from the root of the repo:
        ```
        pip install -e .
        ```
        
        ## Testing
        
        Package requirements to run the tests:
        - pytest
        - numpy
        
        General testing is done with *pytest* (from the root of the repository):
        ```bash
        pytest
        ```
        (**Note**: close the interactive countdown window at the end of the pytest run to finish the test.)
        
        Additional testing of interactive command line for real-time timer control can be done by running the example file from the root of the repository.
        ```bash
        python -m example
        ```
        
        See also *Accuracy Test* paragraph above to run performance tests for constant-duration loops with the `Timer` class.
        
        ## Contributing
        
        Issues and Pull requests must be submitted on GitHub (https://github.com/ovinc/oclock) with commits (preferably squashed into a single commit) in branch *authors*.
        
        Version number is automatically extracted from git tag using *setuptools_scm*. Git tags are added by the repo's maintainer.
        
        # Requirements
        
        Python 3.x
        
        (Tests only made from python 3.5 to python 3.9 included)
        
        ### Version-specific requirements
        
        | Version | Information  |
        |:-------:|:------------:|
        |  1.2.1  | Only Python 3.8+ (due to *importlib.metadata*). Later versions switch back to *importlib_metadata* instead. For this reason, this release is yanked from PyPI but can still be installed by specifying the version number exactly. Use v1.2.3 for greater python compatibility (3.5+). |
        
        # Author
        
        Olivier Vincent
        
        ovinc.py@gmail.com
        
        
        # License
        
        BSD 3-Clause (see *LICENCE* file).
        
        BSD 3-Clause License
        
        Copyright (c) 2020, Olivier VINCENT
        All rights reserved.
        
        Redistribution and use in source and binary forms, with or without
        modification, are permitted provided that the following conditions are met:
        
        * Redistributions of source code must retain the above copyright notice, this
          list of conditions and the following disclaimer.
        
        * Redistributions in binary form must reproduce the above copyright notice,
          this list of conditions and the following disclaimer in the documentation
          and/or other materials provided with the distribution.
        
        * Neither the name of the copyright holder nor the names of its
          contributors may be used to endorse or promote products derived from
          this software without specific prior written permission.
        
        THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
        AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
        DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
        FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
        SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
        CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
        OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
        OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
        
Keywords: timing,loops,constant duration,cancellable,modifiable,countdown,context manager,gui
Platform: UNKNOWN
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Requires-Python: >=3
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