private void checkNaN() throws SimulationException {
double d = 0;
boolean b = false;
d += status.getSimulationTime();
d += status.getPreviousTimeStep();
b |= status.getRocketPosition().isNaN();
b |= status.getRocketVelocity().isNaN();
b |= status.getRocketOrientationQuaternion().isNaN();
b |= status.getRocketRotationVelocity().isNaN();
d += status.getEffectiveLaunchRodLength();
if (Double.isNaN(d) || b) {
log.error(
"Simulation resulted in NaN value:"
+ " simulationTime="
+ status.getSimulationTime()
+ " previousTimeStep="
+ status.getPreviousTimeStep()
+ " rocketPosition="
+ status.getRocketPosition()
+ " rocketVelocity="
+ status.getRocketVelocity()
+ " rocketOrientationQuaternion="
+ status.getRocketOrientationQuaternion()
+ " rocketRotationVelocity="
+ status.getRocketRotationVelocity()
+ " effectiveLaunchRodLength="
+ status.getEffectiveLaunchRodLength());
throw new SimulationException(
"Simulation resulted in not-a-number (NaN) value, please report a bug.");
}
}
@Override
public void optimize(Point initial, OptimizationController control) throws OptimizationException {
if (initial.dim() != 1) {
throw new IllegalArgumentException(
"Only single-dimensional optimization supported, dim=" + initial.dim());
}
log.info("Starting golden section search for optimization");
Point guessAC = null;
Point guessBD = null;
try {
boolean guessedAC;
Point previous = p(0);
double previousValue = Double.NaN;
current = previous;
double currentValue = Double.NaN;
/*
* Initialize the points + computation.
*/
Point a = p(0);
Point d = p(1.0);
Point b = section1(a, d);
Point c = section2(a, d);
functionExecutor.compute(a);
functionExecutor.compute(d);
functionExecutor.compute(b);
functionExecutor.compute(c);
// Wait for points a and d, which normally are already precomputed
functionExecutor.waitFor(a);
functionExecutor.waitFor(d);
boolean continueOptimization = true;
while (continueOptimization) {
/*
* Get values at A & D for guessing.
* These are pre-calculated except during the first step.
*/
double fa, fd;
fa = functionExecutor.getValue(a);
fd = functionExecutor.getValue(d);
/*
* Start calculating possible two next points. The order of evaluation
* is selected based on the function values at A and D.
*/
guessAC = section1(a, c);
guessBD = section2(b, d);
if (Double.isNaN(fd) || fa < fd) {
guessedAC = true;
functionExecutor.compute(guessAC);
functionExecutor.compute(guessBD);
} else {
guessedAC = false;
functionExecutor.compute(guessBD);
functionExecutor.compute(guessAC);
}
/*
* Get values at B and C.
*/
double fb, fc;
functionExecutor.waitFor(b);
functionExecutor.waitFor(c);
fb = functionExecutor.getValue(b);
fc = functionExecutor.getValue(c);
double min = MathUtil.min(fa, fb, fc, fd);
if (Double.isNaN(min)) {
throw new OptimizationException("Unable to compute initial function values");
}
/*
* Update previous and current values for step control.
*/
previousValue = currentValue;
currentValue = min;
previous = current;
if (min == fa) {
current = a;
} else if (min == fb) {
current = b;
} else if (min == fc) {
current = c;
} else {
current = d;
}
/*
* Select next positions. These are already being calculated in the background
* as guessAC and guessBD.
*/
if (min == fa || min == fb) {
d = c;
c = b;
b = guessAC;
functionExecutor.abort(guessBD);
guessBD = null;
log.debug("Selecting A-C region, a=" + a.get(0) + " c=" + c.get(0));
if (guessedAC) {
guessSuccess++;
} else {
guessFailure++;
}
} else {
a = b;
b = c;
c = guessBD;
functionExecutor.abort(guessAC);
guessAC = null;
log.debug("Selecting B-D region, b=" + b.get(0) + " d=" + d.get(0));
if (!guessedAC) {
guessSuccess++;
} else {
guessFailure++;
}
}
/*
* Check optimization control.
*/
continueOptimization =
control.stepTaken(previous, previousValue, current, currentValue, c.get(0) - a.get(0));
if (Thread.interrupted()) {
throw new InterruptedException();
}
}
} catch (InterruptedException e) {
log.info("Optimization was interrupted with InterruptedException");
}
if (guessAC != null) {
functionExecutor.abort(guessAC);
}
if (guessBD != null) {
functionExecutor.abort(guessBD);
}
log.info(
"Finishing optimization at point " + getOptimumPoint() + " value " + getOptimumValue());
log.info("Optimization statistics: " + getStatistics());
}
@Override
public FlightData simulate(SimulationConditions simulationConditions) throws SimulationException {
Set<MotorId> motorBurntOut = new HashSet<MotorId>();
// Set up flight data
FlightData flightData = new FlightData();
// Set up rocket configuration
Configuration configuration = setupConfiguration(simulationConditions);
MotorInstanceConfiguration motorConfiguration = setupMotorConfiguration(configuration);
if (motorConfiguration.getMotorIDs().isEmpty()) {
throw new MotorIgnitionException("No motors defined in the simulation.");
}
// Initialize the simulation
currentStepper = flightStepper;
status = initialStatus(configuration, motorConfiguration, simulationConditions, flightData);
status = currentStepper.initialize(status);
SimulationListenerHelper.fireStartSimulation(status);
// Get originating position (in case listener has modified launch position)
Coordinate origin = status.getRocketPosition();
Coordinate originVelocity = status.getRocketVelocity();
try {
double maxAlt = Double.NEGATIVE_INFINITY;
// Start the simulation
while (handleEvents()) {
// Take the step
double oldAlt = status.getRocketPosition().z;
if (SimulationListenerHelper.firePreStep(status)) {
// Step at most to the next event
double maxStepTime = Double.MAX_VALUE;
FlightEvent nextEvent = status.getEventQueue().peek();
if (nextEvent != null) {
maxStepTime = MathUtil.max(nextEvent.getTime() - status.getSimulationTime(), 0.001);
}
log.verbose(
"BasicEventSimulationEngine: Taking simulation step at t="
+ status.getSimulationTime());
currentStepper.step(status, maxStepTime);
}
SimulationListenerHelper.firePostStep(status);
// Calculate values for custom expressions
FlightDataBranch data = status.getFlightData();
ArrayList<CustomExpression> allExpressions =
status.getSimulationConditions().getSimulation().getCustomExpressions();
for (CustomExpression expression : allExpressions) {
data.setValue(expression.getType(), expression.evaluate(status));
}
// Check for NaN values in the simulation status
checkNaN();
// Add altitude event
addEvent(
new FlightEvent(
FlightEvent.Type.ALTITUDE,
status.getSimulationTime(),
status.getConfiguration().getRocket(),
new Pair<Double, Double>(oldAlt, status.getRocketPosition().z)));
if (status.getRocketPosition().z > maxAlt) {
maxAlt = status.getRocketPosition().z;
}
// Position relative to start location
Coordinate relativePosition = status.getRocketPosition().sub(origin);
// Add appropriate events
if (!status.isLiftoff()) {
// Avoid sinking into ground before liftoff
if (relativePosition.z < 0) {
status.setRocketPosition(origin);
status.setRocketVelocity(originVelocity);
}
// Detect lift-off
if (relativePosition.z > 0.02) {
addEvent(new FlightEvent(FlightEvent.Type.LIFTOFF, status.getSimulationTime()));
}
} else {
// Check ground hit after liftoff
if (status.getRocketPosition().z < 0) {
status.setRocketPosition(status.getRocketPosition().setZ(0));
addEvent(new FlightEvent(FlightEvent.Type.GROUND_HIT, status.getSimulationTime()));
addEvent(new FlightEvent(FlightEvent.Type.SIMULATION_END, status.getSimulationTime()));
}
}
// Check for launch guide clearance
if (!status.isLaunchRodCleared()
&& relativePosition.length() > status.getSimulationConditions().getLaunchRodLength()) {
addEvent(new FlightEvent(FlightEvent.Type.LAUNCHROD, status.getSimulationTime(), null));
}
// Check for apogee
if (!status.isApogeeReached() && status.getRocketPosition().z < maxAlt - 0.01) {
addEvent(
new FlightEvent(
FlightEvent.Type.APOGEE,
status.getSimulationTime(),
status.getConfiguration().getRocket()));
}
// Check for burnt out motors
for (MotorId motorId : status.getMotorConfiguration().getMotorIDs()) {
MotorInstance motor = status.getMotorConfiguration().getMotorInstance(motorId);
if (!motor.isActive() && motorBurntOut.add(motorId)) {
addEvent(
new FlightEvent(
FlightEvent.Type.BURNOUT,
status.getSimulationTime(),
(RocketComponent) status.getMotorConfiguration().getMotorMount(motorId),
motorId));
}
}
}
} catch (SimulationException e) {
SimulationListenerHelper.fireEndSimulation(status, e);
throw e;
}
SimulationListenerHelper.fireEndSimulation(status, null);
flightData.addBranch(status.getFlightData());
if (!flightData.getWarningSet().isEmpty()) {
log.info("Warnings at the end of simulation: " + flightData.getWarningSet());
}
// TODO: HIGH: Simulate branches
return flightData;
}
/**
* Handles events occurring during the flight from the event queue. Each event that has occurred
* before or at the current simulation time is processed. Suitable events are also added to the
* flight data.
*/
private boolean handleEvents() throws SimulationException {
boolean ret = true;
FlightEvent event;
for (event = nextEvent(); event != null; event = nextEvent()) {
// Ignore events for components that are no longer attached to the rocket
if (event.getSource() != null
&& event.getSource().getParent() != null
&& !status.getConfiguration().isStageActive(event.getSource().getStageNumber())) {
continue;
}
// Call simulation listeners, allow aborting event handling
if (!SimulationListenerHelper.fireHandleFlightEvent(status, event)) {
continue;
}
if (event.getType() != FlightEvent.Type.ALTITUDE) {
log.verbose("BasicEventSimulationEngine: Handling event " + event);
}
if (event.getType() == FlightEvent.Type.IGNITION) {
MotorMount mount = (MotorMount) event.getSource();
MotorId motorId = (MotorId) event.getData();
MotorInstance instance = status.getMotorConfiguration().getMotorInstance(motorId);
if (!SimulationListenerHelper.fireMotorIgnition(status, motorId, mount, instance)) {
continue;
}
}
if (event.getType() == FlightEvent.Type.RECOVERY_DEVICE_DEPLOYMENT) {
RecoveryDevice device = (RecoveryDevice) event.getSource();
if (!SimulationListenerHelper.fireRecoveryDeviceDeployment(status, device)) {
continue;
}
}
// Check for motor ignition events, add ignition events to queue
for (MotorId id : status.getMotorConfiguration().getMotorIDs()) {
MotorMount mount = status.getMotorConfiguration().getMotorMount(id);
RocketComponent component = (RocketComponent) mount;
if (mount.getIgnitionEvent().isActivationEvent(event, component)) {
addEvent(
new FlightEvent(
FlightEvent.Type.IGNITION,
status.getSimulationTime() + mount.getIgnitionDelay(),
component,
id));
}
}
// Check for stage separation event
for (int stageNo : status.getConfiguration().getActiveStages()) {
if (stageNo == 0) continue;
Stage stage = (Stage) status.getConfiguration().getRocket().getChild(stageNo);
if (stage.getSeparationEvent().isSeparationEvent(event, stage)) {
addEvent(
new FlightEvent(
FlightEvent.Type.STAGE_SEPARATION,
event.getTime() + stage.getSeparationDelay(),
stage));
}
}
// Check for recovery device deployment, add events to queue
Iterator<RocketComponent> rci = status.getConfiguration().iterator();
while (rci.hasNext()) {
RocketComponent c = rci.next();
if (!(c instanceof RecoveryDevice)) continue;
if (((RecoveryDevice) c).getDeployEvent().isActivationEvent(event, c)) {
// Delay event by at least 1ms to allow stage separation to occur first
addEvent(
new FlightEvent(
FlightEvent.Type.RECOVERY_DEVICE_DEPLOYMENT,
event.getTime() + Math.max(0.001, ((RecoveryDevice) c).getDeployDelay()),
c));
}
}
// Handle event
switch (event.getType()) {
case LAUNCH:
{
status.getFlightData().addEvent(event);
break;
}
case IGNITION:
{
// Ignite the motor
MotorMount mount = (MotorMount) event.getSource();
RocketComponent component = (RocketComponent) mount;
MotorId motorId = (MotorId) event.getData();
MotorInstanceConfiguration config = status.getMotorConfiguration();
config.setMotorIgnitionTime(motorId, event.getTime());
status.setMotorIgnited(true);
status.getFlightData().addEvent(event);
break;
}
case LIFTOFF:
{
// Mark lift-off as occurred
status.setLiftoff(true);
status.getFlightData().addEvent(event);
break;
}
case LAUNCHROD:
{
// Mark launch rod as cleared
status.setLaunchRodCleared(true);
status.getFlightData().addEvent(event);
break;
}
case BURNOUT:
{
// If motor burnout occurs without lift-off, abort
if (!status.isLiftoff()) {
throw new SimulationLaunchException("Motor burnout without liftoff.");
}
// Add ejection charge event
String id = status.getConfiguration().getMotorConfigurationID();
MotorMount mount = (MotorMount) event.getSource();
double delay = mount.getMotorDelay(id);
if (delay != Motor.PLUGGED) {
addEvent(
new FlightEvent(
FlightEvent.Type.EJECTION_CHARGE,
status.getSimulationTime() + delay,
event.getSource(),
event.getData()));
}
status.getFlightData().addEvent(event);
break;
}
case EJECTION_CHARGE:
{
status.getFlightData().addEvent(event);
break;
}
case STAGE_SEPARATION:
{
// TODO: HIGH: Store lower stages to be simulated later
RocketComponent stage = event.getSource();
int n = stage.getStageNumber();
status.getConfiguration().setToStage(n - 1);
status.getFlightData().addEvent(event);
break;
}
case APOGEE:
// Mark apogee as reached
status.setApogeeReached(true);
status.getFlightData().addEvent(event);
break;
case RECOVERY_DEVICE_DEPLOYMENT:
RocketComponent c = event.getSource();
int n = c.getStageNumber();
// Ignore event if stage not active
if (status.getConfiguration().isStageActive(n)) {
// TODO: HIGH: Check stage activeness for other events as well?
// Check whether any motor in the active stages is active anymore
for (MotorId motorId : status.getMotorConfiguration().getMotorIDs()) {
int stage =
((RocketComponent) status.getMotorConfiguration().getMotorMount(motorId))
.getStageNumber();
if (!status.getConfiguration().isStageActive(stage)) continue;
if (!status.getMotorConfiguration().getMotorInstance(motorId).isActive()) continue;
status.getWarnings().add(Warning.RECOVERY_DEPLOYMENT_WHILE_BURNING);
}
// Check for launch rod
if (!status.isLaunchRodCleared()) {
status
.getWarnings()
.add(
Warning.fromString(
"Recovery device device deployed while on " + "the launch guide."));
}
// Check current velocity
if (status.getRocketVelocity().length() > 20) {
// TODO: LOW: Custom warning.
status
.getWarnings()
.add(
Warning.fromString(
"Recovery device deployment at high "
+ "speed ("
+ UnitGroup.UNITS_VELOCITY.toStringUnit(
status.getRocketVelocity().length())
+ ")."));
}
status.setLiftoff(true);
status.getDeployedRecoveryDevices().add((RecoveryDevice) c);
this.currentStepper = this.landingStepper;
this.status = currentStepper.initialize(status);
status.getFlightData().addEvent(event);
}
break;
case GROUND_HIT:
status.getFlightData().addEvent(event);
break;
case SIMULATION_END:
ret = false;
status.getFlightData().addEvent(event);
break;
case ALTITUDE:
break;
}
}
// If no motor has ignited, abort
if (!status.isMotorIgnited()) {
throw new MotorIgnitionException("No motors ignited.");
}
return ret;
}