cimba 0.2.1

Python bindings for Cimba, a multithreaded discrete-event-simulation C library

Cimba Python

Fast discrete event simulation for Python

Cimba Python is a Python interface to Cimba, a multithreaded discrete event simulation engine written in C and assembly.

It is designed for Python simulation models that need more speed than pure Python event scheduling can usually provide. In the included M/M/1 benchmark, Cimba Python runs about 8.5-8.9x faster than SimPy, while keeping model code in Python.

On an AMD Ryzen 7 9700X under WSL Ubuntu 24.04, averaged over 10 runs:

Benchmark	SimPy	Cimba Python	Cimba C
Single core, single trial	3.185 s	0.375 s	0.095 s
Multicore, 100 trials	41.820 s	4.698 s	1.178 s

The benchmark data and charts are in benchmarks/AMD_Ryzen_7_9700X_WSL.ods.

Install

pip install cimba

or with uv:

uv add cimba

Python 3.13 or newer is required. The PyPI wheels embed the Cimba C library, so you do not need to install Cimba separately.

What is it?

Cimba Python gives Python models access to Cimba's native simulation engine: processes, event queues, buffers, object queues, priority queues, resources, conditions, random distributions, time series, and summary statistics.

What does the code look like?

import cimba


def arrival(queue):
    while True:
        cimba.hold(cimba.exponential(1.0 / 0.75))
        queue.put(1)


def service(queue):
    while True:
        queue.get(1)
        cimba.hold(cimba.exponential(1.0))


with cimba.Simulation(seed=123) as sim:
    queue = cimba.Buffer("Queue")
    queue.start_recording()

    cimba.Process("Arrival", arrival, queue).start()
    cimba.Process("Service", service, queue).start()

    sim.stop_at(1000.0)
    sim.execute()

    queue.stop_recording()
    print(queue.history().summary().mean)

More examples, tutorials, topical guides, and the API reference are in the documentation.

License

Cimba Python is licensed under Apache-2.0. See LICENSE and NOTICE.

The bundled Cimba C library is also Apache-2.0 licensed. See subprojects/cimba/NOTICE for attribution.