Building Blocks

A model is made of a few kinds of parts. This page is the map: which block models what, and what it is called in each way of writing. Each block has a page of its own.

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What It Is

An entity is the thing that flows through a model: an order, a visitor, a support call. It enters through an arrival, does the work its task describes, holds a resource while it works, may take from or add to a store or container, and goes on to the next task. What Is DES? explains the simulation they run in. Look at how the blocks connect:

Block	What it models	YAML	Builder	Low-level	Page
Arrival	how often an entity enters, and what it starts with	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	packers, benches, lanes: whole units held by a task	resources	add_resource	DynamicResource	Resources
Container	an amount, such as a stock of boxes, that tasks take and add	containers	add_container	DynamicContainer	Stores and Containers
Store	items, such as parcels on a shelf, that tasks put and get	stores	add_store	DynamicStore	Stores and Containers
Task flow	the task that follows a finished one, and what the entity carries	next, attributes, set	next=, attributes=, set=	Router, Entity	Task Flow
Process	anything else that runs over time: a break, a drift, a schedule	processes	add_process	env.process	Tasks and Processes
Statistics	what the run measures about itself	stats	with_stats	env.setup_stats, env.stats	Statistics
Variable	any other live value, such as a speed	variables	add_variable	SimParameter(variables=...)	Live Parameters

Tutorial: the Shop, in the Learn section, puts them together one at a time, in a small online shop.