Concepts

At the core, GWR lets you describe:

• Tasks that model independent activities.
• Data objects that represent information or physical items moving between tasks.
• Events that wake tasks up.
• Clocks that advance simulated time.
• State such as queues and data stores that create contention.
• Metrics and traces that give visibility of what happens in the model.

Core Building Blocks

Tasks

Tasks are the concurrent parts of the model implemented as async functions. They wait for data, time, or a signal, then perform some action or update state which may trigger other tasks.

Data

Simulation objects model data that is acted on by tasks.

Events

Events provide the wake-up mechanism between tasks. They are useful for notifications such as “task complete”, “data is ready”, “time reached” or “space is available”.

Clocks

Clocks make modelling time explicit as tasks choose when they want to wait for time to advance a number of clock ticks to represent actions that take time.

State

Queues and data stores are examples of state that handle data that the tasks act on.

Metrics

A model can emit log messages and trace data to help inspect why a result occurred, not just what the final totals were. These can either be written textually to console, a space efficient binary format, or inspected with tools like Perfetto.