Crate desque

Overview

desque is a lightweight framework for developing discrete-event simulations, depending only on the Rust standard library by default. While desque provides little more than an event queue and a runner, both constructs make use of generic templating to provide you with control over how a desque simulation operates:

• The Event trait guarantees exclusive access to the simulation’s state at runtime, without forcing you to choose between interior mutability or unsafe access to mutable, static data.
• Parameterizing over the SimState trait gives full access to your use case’s implementing type while executing events, with no requirements placed on that type.
• The Simulation struct expects each event to be capable of failing, gracefully halting execution if an event returns an error to give client code the option of handling it outside the event loop.
• Parameterizing over the SimTime trait gives full control over how events are sequenced at runtime, determined entirely through your type’s implementation of the Ord supertrait.

The expectation in desque that a Simulation own all data associated with a replication also supports the application of variance-reduction techniques from the statistical field known as design of experiments. For example, a desque simulation can use the antithetic variates technique by creating paired random-number generators and handing each generator (along with copies of initializing data) to a different thread. As desque provides each executing event exclusive access to simulation state, it is straightforward for simulation developers to ensure that replications on separate threads are isolated from each other, shielding them from unplanned dependencies which may affect statistical results.

Features

desque offers one feature, ordered-float, which provides the option to add a dependency on the ordered-float crate so that its OrderedFloat and NotNan structs may be used as SimTime. Its std feature will be enabled, as desque requires access to the standard library anyway, but no other features of ordered-float are enforced - add them in your Cargo.toml if you need them. By default, this feature is disabled in desque to avoid a potentially unnecessary dependency.

Modules

serial

For building and running a simulation entirely from one thread.

threadsafe

For building and running a simulation across multiple threads.

Enums

Error

Errors that may be encountered while executing a simulation.

Traits

SimState

The generic type used for a simulation’s overall state.

SimTime

The generic type used for a simulation’s clock.

Type Aliases

Result

Simplifies the signatures of various functions in desque.