SimPy
SimPy stands for “Simulation in Python”, is a process-based discrete-event simulation framework based on standard Python.[1] It enables users to model active components such as customers, vehicles, or agents as simple Python generator functions. SimPy is released as open source software under the MIT License. The first version was released in December 2002.[2]
| Original author(s) | Klaus G. Müller, Tony Vignaux |
|---|---|
| Developer(s) | Ontje Lünsdorf, Stefan Scherfke |
| Initial release | September 17, 2002 |
| Stable release | 4.1.1 / November 12, 2023 |
| Repository |
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| Written in | Python |
| Operating system | Cross-platform |
| Type | Discrete event simulation |
| License | MIT |
| Website | simpy |
Overview edit
Its event dispatcher is based on Python's generators and can be used for asynchronous networking or to implement multi-agent systems (with both, simulated and real communication). Simulations can be performed “as fast as possible”, in real time (wall clock time) or by manually stepping through the events. Though it is theoretically possible to do continuous simulations with SimPy, it lacks features to support them. However, for simulations with a fixed step size where processes don't interact with each other or with shared resources, a simple while loop is sufficient.[3]
Additionally, SimPy provides different types of shared resources to simulate congestion points that have limited capacity, such as servers, checkout counters, and tunnels. In version 3.1 and above, SimPy offers monitoring capabilities to assist in collecting statistics about processes and resources.
SimPy 3.0 requires Python 3.,[4] while SimPy 4.0 requires Python 3.6+. SimPy distribution contains tutorials,[5] documentation, and examples.
Example edit
The following is a SimPy simulation [6] showing a clock process that prints the current simulation time at each step:
>>> import simpy >>> >>> def clock(env, name, tick): ... while True: ... print(name, env.now) ... yield env.timeout(tick) ... >>> env = simpy.Environment() >>> env.process(clock(env, 'fast', 0.5)) <Process(clock) object at 0x...> >>> env.process(clock(env, 'slow', 1)) <Process(clock) object at 0x...> >>> env.run(until=2) fast 0 slow 0 fast 0.5 slow 1 fast 1.0 fast 1.5 References edit
- ^ Iwata, Curtis; Mavris, Dimitri (2013-01-01). "Object-Oriented Discrete Event Simulation Modeling Environment for Aerospace Vehicle Maintenance and Logistics Process". Procedia Computer Science. 2013 Conference on Systems Engineering Research. 16: 187–196. doi:10.1016/j.procs.2013.01.020. ISSN 1877-0509.
- ^ Xiong, Xinli; Ma, Linru; Cui, Chao (2020-01-13). "Simulation Environment of Evaluation and Optimization for Moving Target Defense: A SimPy Approach". Proceedings of the 2019 9th International Conference on Communication and Network Security. ICCNS '19. New York, NY, USA: Association for Computing Machinery: 114–117. doi:10.1145/3371676.3371692. ISBN 978-1-4503-7662-4.
- ^ Olaitan, Oladipupo; Geraghty, John; Young, Paul; Dagkakis, Georgios; Heavey, Cathal; Bayer, Martin; Perrin, Jerome; Robin, Sebastien (2014-01-01). "Implementing ManPy, a Semantic-free Open-source Discrete Event Simulation Package, in a Job Shop". Procedia CIRP. 8th International Conference on Digital Enterprise Technology - DET 2014 Disruptive Innovation in Manufacturing Engineering towards the 4th Industrial Revolution. 25: 253–260. doi:10.1016/j.procir.2014.10.036. ISSN 2212-8271.
- ^ "SimPy History & Change Log — SimPy 4.0.2.dev1+g2973dbe documentation".
- ^ Zinoviev, Dmitry (February 2018). "Discrete Event Simulation. It's Easy with SimPy!". PragPub (104): 1–16.
- ^ Scherfke, Stefan (July 25, 2014). "Discrete-event simulation with SimPy" (PDF). p. 5. Retrieved August 10, 2016.