Glossary¶
- Aerie¶
A suite of planning and scheduling, modeling and simulation, constraint checking and sequencing tools.
- Activity Type¶
A named action or behavior of the system.
- Cell¶
A container for a piece of simulation state. To guarantee correctness of simulation results, all mutable state must be tracked in cells.
- Daemon Task¶
A Task that is spawned during mission model initialization, meaning it starts execution at the beginning of simulation rather than as a result of a Directive.
- Directive¶
A request to instantiate a certain Activity Type with certain arguments at a certain time.
- Effect¶
An action that changes the value of a cell. Effects are defined as functions from an old value to a new value.
- Effect Model¶
The body of the function describing an activity’s behavior during simulation.
- Merlin¶
The modeling and simulation component of Aerie.
- Mission model¶
A description of a system that Aerie understands. This primarily includes definitions of Activity Types and Resources.
- Profile¶
A piece-wise defined function from time to a value
- Profile Segment¶
A single piece of the Profile with a start and end time. Profile segments within one profile must be contiguous and non-overlapping.
- Resource¶
A
- Span¶
A component of simulation results representing a start time, a duration, an optional parent, and some metadata.
- Validation¶
A predicate on the arguments to an activity. Violation of a predicate does not preclude execution of the activity, but rather serves as a warning.
Other terminology:¶
There are some general terms that Aerie uses very specifically, that may not be worth a glossary entry, but do deserve some attention.
Parameters vs Arguments¶
Take as an example the add1 function below:
def add1(x):
return x + 1
and this invocation of the add function:
add1(5)
In this example, x is a parameter of the add1 function, while 5 is an argument to the invocation of the add1
function.
Register vs Registrar¶
A Register is an analogy to a processor register, which can store
a single value at a time, and supports the get operation to read that value, and the set operation to overwrite the
entire value.
A Registrar means a “record-keeper” - you can “register” (verb) something with a registrar. In pymerlin, the
registrar is an object provided to the mission model at initialization time, which the model can use to register
its cells and resources.