import logging
import threading
from CBD.depGraph import createDepGraph
from CBD.loopsolvers.linearsolver import LinearSolver
from CBD.realtime.threadingBackend import ThreadingBackend, Platform
from CBD.scheduling import TopologicalScheduler
from CBD.tracers import Tracers
from CBD.state_events.locators import RegulaFalsiStateEventLocator
import CBD.realtime.accurate_time as time
_TQDM_FOUND = True
try:
from tqdm import tqdm
except ImportError:
_TQDM_FOUND = False
[docs]class Simulator:
"""
Simulator for a CBD model. Allows for execution of the simulation.
This class implements the semantics of CBDs.
Args:
model (CBD.Core.CBD): A :class:`CBD` model to simulate.
:Defaults:
The following properties further define the internal mechanisms of
the simulator. As a handy look-up table, all defaults are listed
in the table below. Take a look at the :code:`See Also` column for
more info on the property.
.. list-table::
:widths: 20 40 40
:header-rows: 1
* - Property
- Default
- See Also
* - real-time?
- :code:`False`
- :func:`setRealTime`
* - real-time scale
- 1.0
- :func:`setRealTime`
* - termination time
- :code:`float('inf')`
- :func:`setTerminationTime`
* - termination condition
- :code:`None`
- :func:`setTerminationCondition`
* - scheduler
- :class:`CBD.scheduling.TopologicalScheduler`
- :func:`setScheduler`
* - threading platform (subsystem)
- :class:`CBD.realtime.threadingPython.threadingPython`
- :func:`setRealTimePlatform`, :func:`setRealTimePlatformThreading`,
:func:`setRealTimePlatformTk`, :func:`setRealTimePlatformGameLoop`
* - progress bar?
- :code:`False`
- :func:`setProgressBar`
* - strong component system solver
- :class:`CBD.linearsolver.LinearSolver`
- :func:`setAlgebraicLoopSolver`
* - state event locator
- :class:`CBD.state_events.locators.RegulaFalsiStateEventLocator`
- :func:`setStateEventLocator`
"""
def __init__(self, model):
self.model = model
self.__deltaT = 1.0
self.__realtime = False
self.__finished = True
self.__stop_requested = False
# scale of time in the simulation.
self.__realtime_scale = 1.0
# maximal amount of events with delay 0
self.__realtime_counter_max = 100
# current amount of events
self.__realtime_counter = self.__realtime_counter_max
# Starting time of the simulation
self.__realtime_start_time = 0.0
self.__termination_time = float('inf')
self.__termination_condition = None
# simulation data [dep graph, strong components, curIt]
self.__sim_data = [None, None, 0]
# self.__stepsize_backend = Fixed(self.__deltaT)
self.__scheduler = TopologicalScheduler()
self.__threading_backend = None
self.__threading_backend_subsystem = Platform.PYTHON
self.__threading_backend_args = []
self.__progress = False
self.__progress_event = None
self.__progress_finished = True
self.__logger = logging.getLogger("CBD")
self.__tracer = Tracers(self)
self.__lasttime = None
self.__event_bus = []
self.__events = {
"started": [],
"finished": [],
"prestep": [],
"poststep": [],
"clock_update": []
}
self.__state_events = []
self.__stel = None
self.setStateEventLocator(RegulaFalsiStateEventLocator())
# TODO: make this variable, given more solver implementations
# self.__solver = SympySolver(self.__logger)
self.__solver = LinearSolver(self.__logger)
[docs] def run(self, term_time=None):
"""
Simulates the model.
Args:
term_time (float): When not :code:`None`, overwrites the
termination time with the new value.
"""
self.__finished = False
self.__stop_requested = False
if term_time is not None:
self.__termination_time = term_time
if self.getClock() is None:
self.model.addFixedRateClock("clock", self.__deltaT)
self.__sim_data = [None, None, 0]
self.__progress_finished = False
if self.__threading_backend is None:
# If there is still a backend, it is the same, so keep it!
self.__threading_backend = ThreadingBackend(self.__threading_backend_subsystem,
self.__threading_backend_args)
if _TQDM_FOUND and self.__progress and self.__termination_time < float('inf'):
# Setup progress bar if possible
thread = threading.Thread(target=self.__progress_update)
thread.daemon = True
thread.start()
if self.__realtime:
self.__realtime_start_time = time.time()
self.__lasttime = 0.0
self.__threading_backend.run_on_new_thread(self.__tracer.thread_loop)
self.__threading_backend.run_on_new_thread(self.__event_thread_loop)
self.signal("started")
if self.__realtime:
# Force execute the first iteration now. This way iteration n (n > 0) is
# computed before the real-time is at time n. This allows the computation
# of exact LCC (and possible rewinds) before the real-time clock is at that
# point.
# TODO: Maybe only do this if there are LCC to be checked?
# There is no other reason to "run" earlier than required.
self._do_single_step()
self.__threading_backend.wait(0.0, self.__runsim)
else:
self.__runsim()
def __finish(self):
"""
Terminate the simulation.
"""
if not self.__progress:
# Whenever the progress bar is initialized, wait until it ends
self.__progress_finished = True
self.__tracer.stopTracers()
self.signal("finished")
self.__finished = True
# Make sure all events are executed
self.__threading_backend.wait(0.0, lambda: self.__event_thread_loop(10))
def __check(self):
"""
Checks if the simulation still needs to continue.
This is done based on the termination time and condition.
Returns:
:code:`True` if the simulation needs to be terminated and
:code:`False` otherwise.
"""
ret = self.__stop_requested
if self.__termination_condition is not None:
ret = ret or self.__termination_condition(self.model, self.__sim_data[2])
return ret or self.__termination_time <= self.getTime()
[docs] def stop(self):
"""
Requests a termination of the current running simulation.
"""
self.__stop_requested = True
[docs] def is_running(self):
"""
Returns :code:`True` as long as the simulation is running.
This is a convenience function to keep real-time simulations
alive, or to interact from external sources.
"""
return not self.__progress_finished and not self.__finished
[docs] def getClock(self):
"""
Gets the simulation clock.
See Also:
- :func:`getTime`
- :func:`getRelativeTime`
- :func:`getDeltaT`
- :func:`setDeltaT`
- :class:`CBD.lib.std.Clock`
"""
return self.model.getClock()
[docs] def getTime(self):
"""
Gets the current simulation time.
See Also:
- :func:`getClock`
- :func:`getRelativeTime`
- :func:`getDeltaT`
- :func:`setDeltaT`
- :class:`CBD.lib.std.Clock`
"""
return self.getClock().getTime(self.__sim_data[2])
[docs] def getRelativeTime(self):
"""
Gets the current simulation time, ignoring a starting offset.
See Also:
- :func:`getClock`
- :func:`getTime`
- :func:`getDeltaT`
- :func:`setDeltaT`
- :class:`CBD.lib.std.Clock`
"""
return self.getClock().getRelativeTime(self.__sim_data[2])
[docs] def getDeltaT(self):
"""
Gets the delta in-between iteration steps.
See Also:
- :func:`getClock`
- :func:`getTime`
- :func:`getRelativeTime`
- :func:`setDeltaT`
- :class:`CBD.lib.std.Clock`
"""
return self.getClock().getDeltaT()
[docs] def setDeltaT(self, delta_t):
"""
Sets the delta in-between iteration steps.
Args:
delta_t (float): The delta.
Note:
If the model has a :class:`CBD.lib.std.Clock` block instance, calling
this function will have no effect. It is merely meant to be used for
fixed step simulations.
Note:
While unnecessary, this function is kept for backwards compatibility.
See Also:
- :func:`getClock`
- :func:`getTime`
- :func:`getRelativeTime`
- :func:`getDeltaT`
- :class:`CBD.lib.std.Clock`
- :func:`setStepSize`
"""
self.__deltaT = delta_t
[docs] def setScheduler(self, scheduler):
"""
Sets the scheduler for the simulation. It will identify the
order of the components in a computation.
Args:
scheduler (CBD.scheduling.Scheduler): The scheduler to use.
"""
self.__scheduler = scheduler
[docs] def setAlgebraicLoopSolver(self, solver):
"""
Sets the algebraic loop solver for the simulation. It will identify the
order of the components in a computation.
Args:
solver (CBD.loopsolvers.solver.Solver): The loop solver to use.
"""
self.__solver = solver
[docs] def setStateEventLocator(self, stel):
"""
Sets the state event locator to use when level crossings occur.
Args:
stel (CBD.state_events.locators.StateEventLocator): The new state event to use.
"""
self.__stel = stel
self.__stel.setSimulator(self)
[docs] def registerStateEvent(self, event):
"""
Registers a state event to the current simulator.
Args:
event (CBD.state_events.StateEvent): The event to register.
"""
self.__state_events.append(event)
[docs] def setBlockRate(self, block_path, rate):
"""
Sets the rate for a specific block. Independent of the stepsize, the
rate will identify that a certain block must only execute every
:code:`r` time.
Note:
Blocks for which no rate has been set will always be computed.
Args:
block_path (str): The path of the block to set a rate of.
rate (float): The rate of the block.
"""
self.__scheduler.setRate(block_path, rate)
[docs] def setRealTime(self, enabled=True, scale=1.0):
"""
Makes the simulation run in (scaled) real time.
Args:
enabled (bool): When :code:`True`, realtime simulation will be enabled.
Otherwise, it will be disabled. Defaults to :code:`True`.
scale (float): Optional scaling for the simulation time. When greater
than 1, the simulation will run slower than the actual
time. When < 1, it will run faster.
E.g. :code:`scale = 2.0` will run twice as long.
Defaults to :code:`1.0`.
"""
self.__realtime = enabled
# Scale of 2 => twice as long
self.__realtime_scale = scale
[docs] def setProgressBar(self, enabled=True):
"""
Uses the `tqdm <https://tqdm.github.io/>`_ package to display a progress bar
of the simulation.
Args:
enabled (bool): Whether or not to enable/disable the progress bar.
Defaults to :code:`True` (= show progress bar).
Note:
A progressbar hijacks printing to the console, hence no output shall be
shown.
Raises:
AssertionError: if the :code:`tqdm` module cannot be located.
"""
assert _TQDM_FOUND, "Module tqdm not found. Progressbar is not possible."
self.__progress = enabled
[docs] def setTerminationCondition(self, func):
"""
Sets the system's termination condition.
Args:
func: A function that takes the model and the current iteration as input
and produces :code:`True` if the simulation needs to terminate.
Note:
When set, the progress bars (see :func:`setProgressBar`) may not work as intended.
See Also:
:func:`setTerminationTime`
"""
# TODO: allow termination condition to set progressbar update value?
self.__termination_condition = func
[docs] def setTerminationTime(self, term_time):
"""
Sets the termination time of the system.
Args:
term_time (float): Termination time for the simulation.
"""
self.__termination_time = term_time
[docs] def realtime_gameloop_call(self, time=None):
"""
Do a step in the realtime-gameloop platform.
Args:
time (float): Simulation time to be passed on. Only to be used
for the alternative gameloop backend.
Note:
This function will only work for a :attr:`Platform.GAMELOOP` or a
:attr:`Platform.GLA` simulation, after the :func:`run` method has
been called.
See Also:
- :func:`setRealTimePlatform`
- :func:`setRealTimePlatformGameLoop`
- :func:`run`
"""
self.__threading_backend.step(time)
def _do_single_step(self):
"""
Does a single simulation step.
Warning:
Do **not** use this function to forcefully progress the simulation!
All functionalities for validly simulating and executing a system
that are provided through other parts of the interface should be
sufficient to do a viable simulation. This function should only be
used by the inner workings of the simulator and its functional parts.
"""
pre = time.time()
simT = self.getTime()
self.signal("prestep", pre, simT)
curIt = self.__sim_data[2]
self.__tracer.trace(self.__tracer.traceNewIteration, (curIt, simT))
# Efficiency reasons: dep graph only changes at these times
# in the given set of library blocks.
# TODO: Must be set to "every time" instead.
if curIt < 2 or self.__sim_data[0] is None:
self.__sim_data[0] = createDepGraph(self.model, curIt)
self.__sim_data[1] = self.__scheduler.obtain(self.__sim_data[0], curIt, simT)
self._lcc_compute()
# State Event Location
lcc = float('inf')
lcc_evt = None
for event in self.__state_events:
if not event.fired and self.__stel.detect_signal(event.output_name, event.level, event.direction):
event.fired = True
t = self.__stel.run(event.output_name, event.level, event.direction)
lcc_evt = event
lcc = min(lcc, t)
elif event.fired:
event.fired = False
if lcc != float('inf'):
# TODO: Ideally, the model was cached here and should not be recomputed
self.__stel._function(lcc_evt.output_name, lcc, lcc_evt.level, noop=False)
lcc_evt.event(lcc_evt, lcc, self.model)
self.model._rewind()
# reset to allow for new IC computation
self.model.clearSignals()
self.model.getClock().setStartTime(lcc)
self.__sim_data[0] = None
self.__sim_data[2] = 0
post = time.time()
self.signal("poststep", pre, post, self.getTime())
def _lcc_compute(self):
"""
Computes the blocks at the current time and increases the iteration counter.
Mainly used inside of Level Crossing Detection, hence the name.
"""
self.__computeBlocks(self.__sim_data[1], self.__sim_data[0], self.__sim_data[2])
self.__sim_data[2] += 1
def _rewind(self):
"""
Rewinds the simulator to the previous iteration.
"""
self.__sim_data[2] -= 1
self.model._rewind()
def __realtimeWait(self):
"""
Wait until next realtime event.
Returns:
:code:`True` if a simulation stop is required and
:code:`False` otherwise.
"""
current_time = time.time() - self.__realtime_start_time
next_sim_time = min(self.__termination_time, self.__lasttime + self.getDeltaT())
# Scaled Time
next_sim_time *= self.__realtime_scale
# Subtract the time that we already did our computation
wait_time = next_sim_time - current_time
self.__lasttime = next_sim_time / self.__realtime_scale
if wait_time <= 0.0:
# event is overdue => force execute
self.__realtime_counter -= 1
if self.__realtime_counter < 0:
# Too many overdue events at a time
self.__realtime_counter = self.__realtime_counter_max
self.__threading_backend.wait(0.01, self.__runsim)
return True
return False
self.__realtime_counter = self.__realtime_counter_max
self.__threading_backend.wait(wait_time, self.__runsim)
return True
def __runsim(self):
"""
Do the actual simulation.
"""
self.__realtime_counter = self.__realtime_counter_max
while True:
# Force terminate when the main thread is not active anymore
# There is no need to keep the simulation alive in this case
if not self.__threading_backend.is_alive() or self.__check():
self.__finish()
break
self._do_single_step()
if self.__threading_backend_subsystem == Platform.GLA:
self.__threading_backend.wait(self.getDeltaT(), self.__runsim)
break
if self.__realtime and self.__realtimeWait():
# Next event has been scheduled, kill this process
break
def __computeBlocks(self, sortedGraph, depGraph, curIteration):
"""
Compute the new state of the model.
Args:
sortedGraph: The set of strong components.
depGraph: A dependency graph.
curIteration (int): Current simulation iteration.
"""
for component in sortedGraph:
if not self.__hasCycle(component, depGraph):
block = component[0] # the strongly connected component has a single element
if curIteration == 0 or self.__scheduler.mustCompute(block, self.getTime()):
block.compute(curIteration)
self.__tracer.trace(self.__tracer.traceCompute, (curIteration, block))
else:
# Detected a strongly connected component
self.__solver.checkValidity(self.model.getPath(), component)
solverInput = self.__solver.constructInput(component, curIteration)
solutionVector = self.__solver.solve(solverInput)
for block in component:
if curIteration == 0 or self.__scheduler.mustCompute(block, self.getTime()):
blockIndex = component.index(block)
block.appendToSignal(solutionVector[blockIndex])
self.__tracer.trace(self.__tracer.traceCompute, (curIteration, block))
def __hasCycle(self, component, depGraph):
"""
Determine whether a component is cyclic or not.
Args:
component (list): The set of strong components.
depGraph: The dependency graph.
"""
assert len(component) >= 1, "A component should have at least one element"
if len(component) > 1:
return True
# a strong component of size one may still have a cycle: a self-loop
return depGraph.hasDependency(component[0], component[0])
def __progress_update(self):
"""
Updates the progress bar.
"""
assert _TQDM_FOUND, "Module tqdm not found. Progressbar is not possible."
end = self.__termination_time
pbar = tqdm(total=end, bar_format='{desc}: {percentage:3.0f}%|{bar}| {n:.2f}/{total_fmt} '
'[{elapsed}/{remaining}, {rate_fmt}{postfix}]')
last = 0.0
while not self.__finished:
now = self.getTime()
# print(end, now, last)
pbar.update(min(now, end) - last)
last = now
time.sleep(0.5) # Only update every half a second
if last < end:
pbar.update(end - last)
pbar.close()
# TODO: prints immediately after break pbar...
self.__progress_finished = True
[docs] def connect(self, name, function):
"""
Connect an event with an additional, user-defined function. These functions
will be executed on a separate thread and polled every 50 milliseconds.
Warning:
It is expected that the passed function terminates at a certain point
in time, to prevent an infinitely running process.
Warning:
There is no guarantee that these functions will be executed in-order of
connection. For safety, it is best to see these events as not thread-safe.
The functions will be called in the order they were connected to the
events, with the associated arguments. The accepted signals are:
- :code:`started`: Raised whenever the simulation setup has completed,
but before the actual simulation begins.
- :code:`finished`: Raised whenever the simulation finishes.
- :code:`prestep(t, st)`: Raised before a step is done. :code:`t` is the real
time before the step and :code:`st` is the simulation
time.
- :code:`poststep(o, t, st)`: Raised after a step is done. :code:`o` is the real
time before the step, :code:`t` is the real time after
the step and :code:`st` is the simulation time of the
step.
- :code:`clock_update(delta)`: Raised whenever the clock updates. It takes the (new)
delta for the simulation.
Args:
name (str): The name of the signal to raise.
function: A function that will be called with the optional arguments
whenever the event is raised.
"""
if name not in self.__events:
raise ValueError("Invalid signal '%s' in Simulator." % name)
self.__events[name].append(function)
[docs] def signal(self, name, *args):
"""
Raise a signal with a specific name and arguments.
The accepted signals are:
- :code:`started`: Raised whenever the simulation setup has
completed, but before the actual simulation
begins.
- :code:`finished`: Raised whenever the simulation finishes.
- :code:`prestep`: Raised before a step is done.
- :code:`poststep`: Raised after a step is done.
- :code:`clock_update(delta)`: Raised whenever the clock updates. It takes
the (new) delta for the simulation.
Note:
Normally, users do not need to call this function.
Args:
name (str): The name of the signal to raise.
*args: Additional arguments to pass to the connected events.
See Also:
:func:`connect`
"""
if name not in self.__events:
raise ValueError("Invalid signal '%s' in Simulator." % name)
self.__event_bus.append((name, args))
def __event_thread_loop(self, cnt=-1):
i = 0
while (not self.__finished or len(self.__event_bus) > 0) and (cnt == -1 or cnt <= i):
i += 1
if len(self.__event_bus) > 0:
name, args = self.__event_bus.pop()
for evt in self.__events[name]:
evt(*args)
time.sleep(0.05)
[docs] def setCustomTracer(self, *tracer):
"""
Sets a custom tracer.
Args:
*tracer: Either a single instance of a subclass of
:class:`CBD.tracers.baseTracer.BaseTracer` or three elements
:code:`filename` (str), :code:`classname` (str) and
:code:`args` (tuple) to allow instantiation similar to
`PythonPDEVS <http://msdl.cs.mcgill.ca/projects/DEVS/PythonPDEVS>`_.
Note:
Calling this function multiple times with the same arguments will continuously add
new tracers. Thus output to multiple files is possible, though more inefficient than
simply (manually) copying the file at the end.
"""
if len(tracer) == 1:
self.__tracer.registerTracer(tracer[0])
elif len(tracer) == 3:
self.__tracer.registerTracer(tracer)
else:
raise ValueError("Invalid amount of arguments for custom tracer.")
[docs] def setVerbose(self, filename=None):
"""
Sets the verbose tracer.
Args:
filename (Union[str, None]): The file to which the trace must be written.
When :code:`None`, the trace will be written to
the console.
Note:
Calling this function multiple times will continuously add new tracers. Thus output
to multiple files is possible, though more inefficient than simply (manually) copying
the file at the end.
Warning:
Using multiple verbose tracers with the same filename will yield errors and undefined
behaviour.
"""
self.setCustomTracer("tracerVerbose", "VerboseTracer", (filename,))