Building Blocks

A model is made of a few kinds of parts. An entity is the thing that flows through it: a part, an order, a visitor. It enters through an arrival, does the work its task describes, and holds a resource while it works. What Is DES? explains the simulation they run in.

An arrival spawns a task for each entity; the task draws its service time and requests a resource; containers and stores hold quantities and items; processes run anything else; the registry holds every value live; and everything publishes records

Block	What it models	YAML	Builder	Low-level	Page
Arrival	how often an entity enters	`arrivals`	`add_arrival`, `@app.arrival_loop`	a process that waits for a drawn gap	Arrivals and Services
Service	how long a piece of work takes	`services`	`add_service`	a `DistributionConfig` drawn with a `Sampler`	Arrivals and Services
Task	what one entity does, with its events	`tasks`	`@app.task`	a SimPy process	Tasks and Processes
Resource	machines, staff, lanes: whole units held by a task	`resources`	`add_resource`	`DynamicResource`	Resources
Container, store	a quantity, such as fuel, or a collection of items	`containers`	`add_container`	`DynamicContainer`, `DynamicStore`	Resources
Process	anything else that runs over time: a breakdown, a drift, a schedule	`processes`	`add_process`	`env.process`	Tasks and Processes
Variable	any other live value, such as a speed	`variables`	`add_variable`	`SimParameter(variables=...)`	Live Parameters

First Simulation puts the first four together into a small factory.