simpy.core
— SimPy’s core components¶
Core components for event-discrete simulation environments.
-
class
simpy.core.
BaseEnvironment
¶ Base class for event processing environments.
An implementation must at least provide the means to access the current time of the environment (see
now
) and to schedule (seeschedule()
) events as well as processing them (seestep()
.The class is meant to be subclassed for different execution environments. For example, SimPy defines a
Environment
for simulations with a virtual time and and aRealtimeEnvironment
that schedules and executes events in real (e.g., wallclock) time.-
now
¶ The current time of the environment.
-
active_process
¶ The currently active process of the environment.
-
schedule
(event, priority=1, delay=0)¶ Schedule an event with a given priority and a delay.
-
step
()¶ Processes the next event.
-
run
(until=None)¶ Executes
step()
until the given criterion until is met.- If it is
None
(which is the default), this method will return when there are no further events to be processed. - If it is an
Event
, the method will continue stepping until this event has been triggered and will return its value. Raises aRuntimeError
if there are no further events to be processed and the until event was not triggered. - If it is a number, the method will continue stepping until the environment’s time reaches until.
- If it is
-
exit
(value=None)¶ Stop the current process, optionally providing a
value
.This is a convenience function provided for Python versions prior to 3.3. From Python 3.3, you can instead use
return value
in a process.
-
-
class
simpy.core.
Environment
(initial_time=0)¶ Execution environment for an event-based simulation. The passing of time is simulated by stepping from event to event.
You can provide an initial_time for the environment. By default, it starts at
0
.This class also provides aliases for common event types, for example
process
,timeout
andevent
.-
now
¶ The current simulation time.
-
active_process
¶ The currently active process of the environment.
-
event
()¶ Return a new
Event
instance. Yielding this event suspends a process until another process triggers the event.
-
exit
(value=None)¶ Stop the current process, optionally providing a
value
.This is a convenience function provided for Python versions prior to 3.3. From Python 3.3, you can instead use
return value
in a process.
-
schedule
(event, priority=1, delay=0)¶ Schedule an event with a given priority and a delay.
-
step
()¶ Process the next event.
Raise an
EmptySchedule
if no further events are available.
-
run
(until=None)¶ Executes
step()
until the given criterion until is met.- If it is
None
(which is the default), this method will return when there are no further events to be processed. - If it is an
Event
, the method will continue stepping until this event has been triggered and will return its value. Raises aRuntimeError
if there are no further events to be processed and the until event was not triggered. - If it is a number, the method will continue stepping until the environment’s time reaches until.
- If it is
-
-
class
simpy.core.
BoundClass
(cls)¶ Allows classes to behave like methods.
The
__get__()
descriptor is basically identical tofunction.__get__()
and binds the first argument of thecls
to the descriptor instance.-
static
bind_early
(instance)¶ Bind all
BoundClass
attributes of the instance’s class to the instance itself to increase performance.
-
static
-
class
simpy.core.
EmptySchedule
¶ Thrown by an
Environment
if there are no further events to be processed.
-
simpy.core.
Infinity
= inf¶ Convenience alias for infinity