Delta Cycle

DeltaCycle is a Python library for discrete event simulation (DES).

A simulation has two components: a collection of variables, and a collection of tasks. Variables represent the instantaneous state of the simulation. They may be organized into arbitrary data structures. Tasks define how that state evolves. They may appear concurrent, but are scheduled sequentially.

Task execution is subdivided into a sequence of slots. Slots are assigned a monotonically increasing integer value, called time. Multiple tasks may execute in the same slot, and therefore at the same time. The term "delta cycle" refers to a zero-delay subdivision of a time slot. It is the clockwork mechanism behind the illusion of concurrency.

Read the docs! (WIP)

Features

• Kernel: task scheduler
• Task: coroutine wrapper
• Synchronization Primitives:
  • Events
  • Semaphores
  • Queues
• Structured Concurrency:
  • Task Groups (parent/child hierarchy)
  • Interrupts
  • Exceptions
• Model Variables:
  • Singular
  • Aggregate

Example

The following code simulates two clocks running concurrently. The fast clock prints the current time every time step. The slow clock prints the current time every two time steps.

>>> from deltacycle import TaskGroup, now, run, sleep

>>> async def clock(name: str, period: int):
...     while True:
...         print(f"{now()}: {name}")
...         await sleep(period)

>>> async def main():
...     with TaskGroup() as tg:
...         tg.create_task(clock("fast", 1))
...         tg.create_task(clock("slow", 2))

>>> run(main(), until=7)
0: fast
0: slow
1: fast
2: slow
2: fast
3: fast
4: slow
4: fast
5: fast
6: slow
6: fast

Installing

DeltaCycle is available on PyPI:

$ pip install deltacycle

It requires Python 3.12+

Developing

DeltaCycle's repository is on GitHub:

$ git clone https://github.com/cjdrake/deltacycle.git

It is 100% Python, and has no runtime dependencies. Development dependencies are listed in requirements-dev.txt.