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Overview

SimBaseClass is the root class you subclass (or instantiate directly) for every Basilisk simulation. It wraps the C-level SimModel object and exposes Python-level APIs for constructing processes, tasks, and modules, scheduling events, and running the simulation. 
from Basilisk.utilities import SimulationBaseClass

scSim = SimulationBaseClass.SimBaseClass()

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SimBaseClass

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Constructor

SimBaseClass()
Creates a new simulation instance. Initializes TotalSim, empty task and process lists, the event map, and a BSKLogger.

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Process and task setup

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CreateNewProcess
method
Creates a simulation process and registers it with the simulation engine.
proc = scSim.CreateNewProcess(procName, priority=-1)
Returns a simulationArchTypes.ProcessBaseClass object.
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CreateNewTask
method
Creates a simulation task with a fixed update rate.
task = scSim.CreateNewTask(TaskName, TaskRate, FirstStart=0)
Returns a simulationArchTypes.TaskBaseClass object.
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AddModelToTask
method
Adds a module to a named task and optionally sets its execution priority within that task.
scSim.AddModelToTask(TaskName, NewModel, ModelData=None, ModelPriority=-1)
Raises ValueError if TaskName does not match any registered task.

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Simulation execution

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InitializeSimulation
method
Calls SelfInit() and Reset() on every module. You must call this before ExecuteSimulation().
scSim.InitializeSimulation()
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ConfigureStopTime
method
Sets the simulation stop time.
scSim.ConfigureStopTime(TimeStop, StopCondition="<=")
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ExecuteSimulation
method
Runs the simulation until the configured stop time or until a terminal event fires.
scSim.ExecuteSimulation()
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SetProgressBar
method
Enables or disables a terminal progress bar during execution.
scSim.SetProgressBar(True)

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Task control

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enableTask
method
Enables a previously disabled task.
scSim.enableTask(TaskName)
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disableTask
method
Prevents a task from executing without removing it.
scSim.disableTask(TaskName)
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ResetTask
method
Resets all modules in the named task at the current simulation time.
scSim.ResetTask(taskName)

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Visualization

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ShowExecutionOrder
method
Prints the process → task → module execution order to the terminal with color coding.
scSim.ShowExecutionOrder()
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ShowExecutionFigure
method
Renders a matplotlib figure showing the process/task/module hierarchy.
fig = scSim.ShowExecutionFigure(show_plots=False)

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Event system

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createNewEvent
method
Registers a new event handler.
scSim.createNewEvent(eventName, *args, **kwargs)
All extra arguments are forwarded to EventHandlerClass. See the EventHandlerClass section below.
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setEventActivity
method
Activates or deactivates a named event.
scSim.setEventActivity(eventName, activityCommand)
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setAllButCurrentEventActivity
method
Sets activity on all events except currentEventName. Pass useIndex=True to restrict changes to events sharing the same index suffix.
scSim.setAllButCurrentEventActivity(currentEventName, activityCommand, useIndex=False)

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EventHandlerClass

Encapsulates an event’s check strategy, condition, and action. 
EventHandlerClass(
    eventName,
    eventRate=int(1e9),
    eventActive=False,
    conditionFunction=None,
    actionFunction=None,
    conditionTime=None,
    terminal=False,
    exactRateMatch=True,
    conditionList=None,   # deprecated
    actionList=None,      # deprecated
)
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eventName
str
required
Unique name for this event.
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eventRate
int
default:"1000000000"
Check interval in nanoseconds (default 1 s).
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eventActive
bool
default:"false"
Whether the event starts active.
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conditionFunction
callable | None
default:"None"
Function (sim) -> bool. Called to test whether the event should fire. Mutually exclusive with conditionTime and conditionList.
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actionFunction
callable | None
default:"None"
Function (sim) -> None. Called when the condition returns True. Mutually exclusive with actionList.
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conditionTime
int | None
default:"None"
Fire the event at the first timestep at or after this nanosecond value. Mutually exclusive with conditionFunction.
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terminal
bool
default:"false"
If True, the simulation terminates when this event fires.
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exactRateMatch
bool
default:"true"
When True, the event is checked only at exact multiples of eventRate. When False, the event is checked whenever eventRate has elapsed since the last check.

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Usage example

from Basilisk.utilities import SimulationBaseClass, macros

scSim = SimulationBaseClass.SimBaseClass()
proc  = scSim.CreateNewProcess("mainProc")
scSim.CreateNewTask("mainTask", macros.sec2nano(1.0))

# Terminate at t = 100 s
scSim.createNewEvent(
    "stopEvent",
    eventRate=macros.sec2nano(1.0),
    eventActive=True,
    terminal=True,
    conditionTime=macros.sec2nano(100.0),
    actionFunction=lambda sim: None,
)

scSim.InitializeSimulation()
scSim.ConfigureStopTime(macros.sec2nano(200.0))
scSim.ExecuteSimulation()

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Module-level helpers

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SetCArray
function
Writes a Python list into a SWIG-wrapped C array.
SetCArray(InputList, VarType, ArrayPointer)
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getCArray
function
Reads a SWIG-wrapped C array into a Python list.
values = getCArray(varType, arrayPointer, arraySize)
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synchronizeTimeHistories
function
Interpolates multiple time-history arrays onto a common time base.
synced = synchronizeTimeHistories(arrayList)
arrayList is a list of 2-D numpy arrays where column 0 is the time axis.

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