desim stands for Discrete-time Events SIMulator. It aims to be a high quality, easy to use simulation framework for physical or logical systems that are based on processes that are triggered by events and that can cause other events to occur.

It is inspired by the Simpy environment for Python, but with the aim of being more efficient and to provide also a concurrent implementation. To achieve the same ease of use remaining light and efficient, it is based on the experimental coroutines rust feature.

You can read the API documentation here

To use the framework, add the following line to your Cargo.toml:

desim = "0.4"

Version numbers follow the semver convention.

The simulation environment is provided by the Simulation struct, which exposes methods to spawn processes, allocate resources and schedule events. Moreover it offers getters to retrieve the current time and the ordered list of processed events and methods to process the next event in the simulation and to run all the events until a certain condition is verified.

A process is a coroutine that yields a variant of the Effect enum. Using this type the process may interact with the simulation, for example scheduling events or requesting resources.

For more information see the API documentation linked above.

The examples folder contains some simulations that use desim. You can build and run them with cargo run --example <name>.

Feel free to contribute to this project with pull requests and/or issues. All contribution should be under a license compatible with the GNU GPLv3.

Why did you chose the GNU GPL instead of a more permissive license like Apache/MIT?

Because I wrote a piece of free software and I don't want it to be used as the basis of a proprietary one. Improvements of this work or simulation software written using desim as a library should be free software as well.

• 0.4.0 Replace every occurrence of generator with coroutine
• 0.3.0 Allow the definition of custom Resource types.
  WARNING: contains breaking changes:
  • SimGen has been renamed to Process
  • Resource is now a trait and the create_resource method has been updated to take in input a Box<dyn Resource<T>>
  • The old resource type can still be used creating an instance of SimpleResource
• 0.2.0 With generators resume arguments support, add a Simulation Context that is passed to processes on resume and can be used to retrieve the simulation time or the event that caused the generator to resume
• 0.1.0 First release