Initialization

For some reason, GitHub will not show the first top-level heading

Constraint System

A normal variable is generally initialized directly by the programmer. In the presence of multi-way constraints, some variables do not need to be initialized---they will be written as part of the first update. The initial priority order is the same as the definition order.

A computed variable semantically represents the value of an expression; it should (and can only) be initialized not by the programmer, but by the method that writes it. Thus, a computed variable should not be part of a self-loop.