git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java

   1 package net.sf.openrocket.simulation;
   2
   3 import java.util.ArrayList;
   4 import java.util.HashSet;
   5 import java.util.Iterator;
   6 import java.util.Set;
   7
   8 import net.sf.openrocket.aerodynamics.FlightConditions;
   9 import net.sf.openrocket.aerodynamics.Warning;
  10 import net.sf.openrocket.logging.LogHelper;
  11 import net.sf.openrocket.motor.Motor;
  12 import net.sf.openrocket.motor.MotorId;
  13 import net.sf.openrocket.motor.MotorInstance;
  14 import net.sf.openrocket.motor.MotorInstanceConfiguration;
  15 import net.sf.openrocket.rocketcomponent.Configuration;
  16 import net.sf.openrocket.rocketcomponent.LaunchLug;
  17 import net.sf.openrocket.rocketcomponent.MotorMount;
  18 import net.sf.openrocket.rocketcomponent.RecoveryDevice;
  19 import net.sf.openrocket.rocketcomponent.RocketComponent;
  20 import net.sf.openrocket.rocketcomponent.Stage;
  21 import net.sf.openrocket.simulation.exception.MotorIgnitionException;
  22 import net.sf.openrocket.simulation.exception.SimulationException;
  23 import net.sf.openrocket.simulation.exception.SimulationLaunchException;
  24 import net.sf.openrocket.simulation.listeners.SimulationListenerHelper;
  25 import net.sf.openrocket.startup.Application;
  26 import net.sf.openrocket.unit.UnitGroup;
  27 import net.sf.openrocket.util.Coordinate;
  28 import net.sf.openrocket.util.MathUtil;
  29 import net.sf.openrocket.util.Pair;
  30 import net.sf.openrocket.util.Quaternion;
  31
  32
  33 public class BasicEventSimulationEngine implements SimulationEngine {
  34
  35         private static final LogHelper log = Application.getLogger();
  36
  37         // TODO: MEDIUM: Allow selecting steppers
  38         private SimulationStepper flightStepper = new RK4SimulationStepper();
  39         private SimulationStepper landingStepper = new BasicLandingStepper();
  40
  41         private SimulationStepper currentStepper;
  42
  43         private SimulationStatus status;
  44
  45
  46         @Override
  47         public FlightData simulate(SimulationConditions simulationConditions) throws SimulationException {
  48                 Set<MotorId> motorBurntOut = new HashSet<MotorId>();
  49
  50                 // Set up flight data
  51                 FlightData flightData = new FlightData();
  52
  53                 // Set up rocket configuration
  54                 Configuration configuration = setupConfiguration(simulationConditions);
  55                 MotorInstanceConfiguration motorConfiguration = setupMotorConfiguration(configuration);
  56                 if (motorConfiguration.getMotorIDs().isEmpty()) {
  57                         throw new MotorIgnitionException("No motors defined in the simulation.");
  58                 }
  59
  60                 // Initialize the simulation
  61                 currentStepper = flightStepper;
  62                 status = initialStatus(configuration, motorConfiguration, simulationConditions, flightData);
  63                 status = currentStepper.initialize(status);
  64
  65
  66                 SimulationListenerHelper.fireStartSimulation(status);
  67                 // Get originating position (in case listener has modified launch position)
  68                 Coordinate origin = status.getRocketPosition();
  69                 Coordinate originVelocity = status.getRocketVelocity();
  70
  71                 try {
  72                         double maxAlt = Double.NEGATIVE_INFINITY;
  73
  74                         // Start the simulation
  75                         while (handleEvents()) {
  76
  77                                 // Take the step
  78                                 double oldAlt = status.getRocketPosition().z;
  79
  80                                 if (SimulationListenerHelper.firePreStep(status)) {
  81                                         // Step at most to the next event
  82                                         double maxStepTime = Double.MAX_VALUE;
  83                                         FlightEvent nextEvent = status.getEventQueue().peek();
  84                                         if (nextEvent != null) {
  85                                                 maxStepTime = MathUtil.max(nextEvent.getTime() - status.getSimulationTime(), 0.001);
  86                                         }
  87                                         log.verbose("BasicEventSimulationEngine: Taking simulation step at t=" + status.getSimulationTime());
  88                                         currentStepper.step(status, maxStepTime);
  89                                 }
  90                                 SimulationListenerHelper.firePostStep(status);
  91
  92                                 // Calculate values for custom expressions
  93                                 FlightDataBranch data = status.getFlightData();
  94                                 ArrayList<CustomExpression> allExpressions = status.getSimulationConditions().getSimulation().getCustomExpressions();
  95                                 for (CustomExpression expression : allExpressions ) {
  96                                         data.setValue(expression.getType(), expression.evaluate(status));
  97                                 }
  98
  99                                 // Check for NaN values in the simulation status
 100                                 checkNaN();
 101
 102                                 // Add altitude event
 103                                 addEvent(new FlightEvent(FlightEvent.Type.ALTITUDE, status.getSimulationTime(),
 104                                                 status.getConfiguration().getRocket(),
 105                                                 new Pair<Double, Double>(oldAlt, status.getRocketPosition().z)));
 106
 107                                 if (status.getRocketPosition().z > maxAlt) {
 108                                         maxAlt = status.getRocketPosition().z;
 109                                 }
 110
 111
 112                                 // Position relative to start location
 113                                 Coordinate relativePosition = status.getRocketPosition().sub(origin);
 114
 115                                 // Add appropriate events
 116                                 if (!status.isLiftoff()) {
 117
 118                                         // Avoid sinking into ground before liftoff
 119                                         if (relativePosition.z < 0) {
 120                                                 status.setRocketPosition(origin);
 121                                                 status.setRocketVelocity(originVelocity);
 122                                         }
 123                                         // Detect lift-off
 124                                         if (relativePosition.z > 0.02) {
 125                                                 addEvent(new FlightEvent(FlightEvent.Type.LIFTOFF, status.getSimulationTime()));
 126                                         }
 127
 128                                 } else {
 129
 130                                         // Check ground hit after liftoff
 131                                         if (status.getRocketPosition().z < 0) {
 132                                                 status.setRocketPosition(status.getRocketPosition().setZ(0));
 133                                                 addEvent(new FlightEvent(FlightEvent.Type.GROUND_HIT, status.getSimulationTime()));
 134                                                 addEvent(new FlightEvent(FlightEvent.Type.SIMULATION_END, status.getSimulationTime()));
 135                                         }
 136
 137                                 }
 138
 139                                 // Check for launch guide clearance
 140                                 if (!status.isLaunchRodCleared() &&
 141                                                 relativePosition.length() > status.getSimulationConditions().getLaunchRodLength()) {
 142                                         addEvent(new FlightEvent(FlightEvent.Type.LAUNCHROD, status.getSimulationTime(), null));
 143                                 }
 144
 145
 146                                 // Check for apogee
 147                                 if (!status.isApogeeReached() && status.getRocketPosition().z < maxAlt - 0.01) {
 148                                         addEvent(new FlightEvent(FlightEvent.Type.APOGEE, status.getSimulationTime(),
 149                                                         status.getConfiguration().getRocket()));
 150                                 }
 151
 152
 153                                 // Check for burnt out motors
 154                                 for (MotorId motorId : status.getMotorConfiguration().getMotorIDs()) {
 155                                         MotorInstance motor = status.getMotorConfiguration().getMotorInstance(motorId);
 156                                         if (!motor.isActive() && motorBurntOut.add(motorId)) {
 157                                                 addEvent(new FlightEvent(FlightEvent.Type.BURNOUT, status.getSimulationTime(),
 158                                                                 (RocketComponent) status.getMotorConfiguration().getMotorMount(motorId), motorId));
 159                                         }
 160                                 }
 161
 162                         }
 163
 164                 } catch (SimulationException e) {
 165                         SimulationListenerHelper.fireEndSimulation(status, e);
 166                         throw e;
 167                 }
 168
 169                 SimulationListenerHelper.fireEndSimulation(status, null);
 170
 171                 flightData.addBranch(status.getFlightData());
 172
 173                 if (!flightData.getWarningSet().isEmpty()) {
 174                         log.info("Warnings at the end of simulation:  " + flightData.getWarningSet());
 175                 }
 176
 177                 // TODO: HIGH: Simulate branches
 178                 return flightData;
 179         }
 180
 181
 182
 183         private SimulationStatus initialStatus(Configuration configuration,
 184                         MotorInstanceConfiguration motorConfiguration,
 185                         SimulationConditions simulationConditions, FlightData flightData) {
 186
 187                 SimulationStatus init = new SimulationStatus();
 188                 init.setSimulationConditions(simulationConditions);
 189                 init.setConfiguration(configuration);
 190                 init.setMotorConfiguration(motorConfiguration);
 191
 192                 init.setSimulationTime(0);
 193                 init.setPreviousTimeStep(simulationConditions.getTimeStep());
 194                 init.setRocketPosition(Coordinate.NUL);
 195                 init.setRocketVelocity(Coordinate.NUL);
 196                 init.setRocketWorldPosition(simulationConditions.getLaunchSite());
 197
 198                 // Initialize to roll angle with least stability w.r.t. the wind
 199                 Quaternion o;
 200                 FlightConditions cond = new FlightConditions(configuration);
 201                 simulationConditions.getAerodynamicCalculator().getWorstCP(configuration, cond, null);
 202                 double angle = -cond.getTheta() - simulationConditions.getLaunchRodDirection();
 203                 o = Quaternion.rotation(new Coordinate(0, 0, angle));
 204
 205                 // Launch rod angle and direction
 206                 o = o.multiplyLeft(Quaternion.rotation(new Coordinate(0, simulationConditions.getLaunchRodAngle(), 0)));
 207                 o = o.multiplyLeft(Quaternion.rotation(new Coordinate(0, 0, simulationConditions.getLaunchRodDirection())));
 208
 209                 init.setRocketOrientationQuaternion(o);
 210                 init.setRocketRotationVelocity(Coordinate.NUL);
 211
 212
 213                 /*
 214                  * Calculate the effective launch rod length taking into account launch lugs.
 215                  * If no lugs are found, assume a tower launcher of full length.
 216                  */
 217                 double length = simulationConditions.getLaunchRodLength();
 218                 double lugPosition = Double.NaN;
 219                 for (RocketComponent c : configuration) {
 220                         if (c instanceof LaunchLug) {
 221                                 double pos = c.toAbsolute(new Coordinate(c.getLength()))[0].x;
 222                                 if (Double.isNaN(lugPosition) || pos > lugPosition) {
 223                                         lugPosition = pos;
 224                                 }
 225                         }
 226                 }
 227                 if (!Double.isNaN(lugPosition)) {
 228                         double maxX = 0;
 229                         for (Coordinate c : configuration.getBounds()) {
 230                                 if (c.x > maxX)
 231                                         maxX = c.x;
 232                         }
 233                         if (maxX >= lugPosition) {
 234                                 length = Math.max(0, length - (maxX - lugPosition));
 235                         }
 236                 }
 237                 init.setEffectiveLaunchRodLength(length);
 238
 239
 240
 241                 init.setSimulationStartWallTime(System.nanoTime());
 242
 243                 init.setMotorIgnited(false);
 244                 init.setLiftoff(false);
 245                 init.setLaunchRodCleared(false);
 246                 init.setApogeeReached(false);
 247
 248                 init.getEventQueue().add(new FlightEvent(FlightEvent.Type.LAUNCH, 0, simulationConditions.getRocket()));
 249
 250                 init.setFlightData(new FlightDataBranch("MAIN", FlightDataType.TYPE_TIME));
 251                 init.setWarnings(flightData.getWarningSet());
 252
 253                 return init;
 254         }
 255
 256
 257
 258         /**
 259          * Create a rocket configuration from the launch conditions.
 260          *
 261          * @param simulation    the launch conditions.
 262          * @return                              a rocket configuration with all stages attached.
 263          */
 264         private Configuration setupConfiguration(SimulationConditions simulation) {
 265                 Configuration configuration = new Configuration(simulation.getRocket());
 266                 configuration.setAllStages();
 267                 configuration.setMotorConfigurationID(simulation.getMotorConfigurationID());
 268
 269                 return configuration;
 270         }
 271
 272
 273
 274         /**
 275          * Create a new motor instance configuration for the rocket configuration.
 276          *
 277          * @param configuration         the rocket configuration.
 278          * @return                                      a new motor instance configuration with all motors in place.
 279          */
 280         private MotorInstanceConfiguration setupMotorConfiguration(Configuration configuration) {
 281                 MotorInstanceConfiguration motors = new MotorInstanceConfiguration();
 282                 final String motorId = configuration.getMotorConfigurationID();
 283
 284                 Iterator<MotorMount> iterator = configuration.motorIterator();
 285                 while (iterator.hasNext()) {
 286                         MotorMount mount = iterator.next();
 287                         RocketComponent component = (RocketComponent) mount;
 288                         Motor motor = mount.getMotor(motorId);
 289
 290                         if (motor != null) {
 291                                 Coordinate[] positions = component.toAbsolute(mount.getMotorPosition(motorId));
 292                                 for (int i = 0; i < positions.length; i++) {
 293                                         Coordinate position = positions[i];
 294                                         MotorId id = new MotorId(component.getID(), i + 1);
 295                                         motors.addMotor(id, motor.getInstance(), mount, position);
 296                                 }
 297                         }
 298                 }
 299                 return motors;
 300         }
 301
 302         /**
 303          * Handles events occurring during the flight from the event queue.
 304          * Each event that has occurred before or at the current simulation time is
 305          * processed.  Suitable events are also added to the flight data.
 306          */
 307         private boolean handleEvents() throws SimulationException {
 308                 boolean ret = true;
 309                 FlightEvent event;
 310
 311                 for (event = nextEvent(); event != null; event = nextEvent()) {
 312
 313                         // Ignore events for components that are no longer attached to the rocket
 314                         if (event.getSource() != null && event.getSource().getParent() != null &&
 315                                         !status.getConfiguration().isStageActive(event.getSource().getStageNumber())) {
 316                                 continue;
 317                         }
 318
 319                         // Call simulation listeners, allow aborting event handling
 320                         if (!SimulationListenerHelper.fireHandleFlightEvent(status, event)) {
 321                                 continue;
 322                         }
 323
 324                         if (event.getType() != FlightEvent.Type.ALTITUDE) {
 325                                 log.verbose("BasicEventSimulationEngine:  Handling event " + event);
 326                         }
 327
 328                         if (event.getType() == FlightEvent.Type.IGNITION) {
 329                                 MotorMount mount = (MotorMount) event.getSource();
 330                                 MotorId motorId = (MotorId) event.getData();
 331                                 MotorInstance instance = status.getMotorConfiguration().getMotorInstance(motorId);
 332                                 if (!SimulationListenerHelper.fireMotorIgnition(status, motorId, mount, instance)) {
 333                                         continue;
 334                                 }
 335                         }
 336
 337                         if (event.getType() == FlightEvent.Type.RECOVERY_DEVICE_DEPLOYMENT) {
 338                                 RecoveryDevice device = (RecoveryDevice) event.getSource();
 339                                 if (!SimulationListenerHelper.fireRecoveryDeviceDeployment(status, device)) {
 340                                         continue;
 341                                 }
 342                         }
 343
 344
 345
 346                         // Check for motor ignition events, add ignition events to queue
 347                         for (MotorId id : status.getMotorConfiguration().getMotorIDs()) {
 348                                 MotorMount mount = status.getMotorConfiguration().getMotorMount(id);
 349                                 RocketComponent component = (RocketComponent) mount;
 350
 351                                 if (mount.getIgnitionEvent().isActivationEvent(event, component)) {
 352                                         addEvent(new FlightEvent(FlightEvent.Type.IGNITION,
 353                                                         status.getSimulationTime() + mount.getIgnitionDelay(),
 354                                                         component, id));
 355                                 }
 356                         }
 357
 358
 359                         // Check for stage separation event
 360                         for (int stageNo : status.getConfiguration().getActiveStages()) {
 361                                 if (stageNo == 0)
 362                                         continue;
 363
 364                                 Stage stage = (Stage) status.getConfiguration().getRocket().getChild(stageNo);
 365                                 if (stage.getSeparationEvent().isSeparationEvent(event, stage)) {
 366                                         addEvent(new FlightEvent(FlightEvent.Type.STAGE_SEPARATION,
 367                                                         event.getTime() + stage.getSeparationDelay(), stage));
 368                                 }
 369                         }
 370
 371
 372                         // Check for recovery device deployment, add events to queue
 373                         Iterator<RocketComponent> rci = status.getConfiguration().iterator();
 374                         while (rci.hasNext()) {
 375                                 RocketComponent c = rci.next();
 376                                 if (!(c instanceof RecoveryDevice))
 377                                         continue;
 378                                 if (((RecoveryDevice) c).getDeployEvent().isActivationEvent(event, c)) {
 379                                         // Delay event by at least 1ms to allow stage separation to occur first
 380                                         addEvent(new FlightEvent(FlightEvent.Type.RECOVERY_DEVICE_DEPLOYMENT,
 381                                                         event.getTime() + Math.max(0.001, ((RecoveryDevice) c).getDeployDelay()), c));
 382                                 }
 383                         }
 384
 385
 386                         // Handle event
 387                         switch (event.getType()) {
 388
 389                         case LAUNCH: {
 390                                 status.getFlightData().addEvent(event);
 391                                 break;
 392                         }
 393
 394                         case IGNITION: {
 395                                 // Ignite the motor
 396                                 MotorMount mount = (MotorMount) event.getSource();
 397                                 RocketComponent component = (RocketComponent) mount;
 398                                 MotorId motorId = (MotorId) event.getData();
 399                                 MotorInstanceConfiguration config = status.getMotorConfiguration();
 400                                 config.setMotorIgnitionTime(motorId, event.getTime());
 401                                 status.setMotorIgnited(true);
 402                                 status.getFlightData().addEvent(event);
 403
 404                                 break;
 405                         }
 406
 407                         case LIFTOFF: {
 408                                 // Mark lift-off as occurred
 409                                 status.setLiftoff(true);
 410                                 status.getFlightData().addEvent(event);
 411                                 break;
 412                         }
 413
 414                         case LAUNCHROD: {
 415                                 // Mark launch rod as cleared
 416                                 status.setLaunchRodCleared(true);
 417                                 status.getFlightData().addEvent(event);
 418                                 break;
 419                         }
 420
 421                         case BURNOUT: {
 422                                 // If motor burnout occurs without lift-off, abort
 423                                 if (!status.isLiftoff()) {
 424                                         throw new SimulationLaunchException("Motor burnout without liftoff.");
 425                                 }
 426                                 // Add ejection charge event
 427                                 String id = status.getConfiguration().getMotorConfigurationID();
 428                                 MotorMount mount = (MotorMount) event.getSource();
 429                                 double delay = mount.getMotorDelay(id);
 430                                 if (delay != Motor.PLUGGED) {
 431                                         addEvent(new FlightEvent(FlightEvent.Type.EJECTION_CHARGE, status.getSimulationTime() + delay,
 432                                                         event.getSource(), event.getData()));
 433                                 }
 434                                 status.getFlightData().addEvent(event);
 435                                 break;
 436                         }
 437
 438                         case EJECTION_CHARGE: {
 439                                 status.getFlightData().addEvent(event);
 440                                 break;
 441                         }
 442
 443                         case STAGE_SEPARATION: {
 444                                 // TODO: HIGH: Store lower stages to be simulated later
 445                                 RocketComponent stage = event.getSource();
 446                                 int n = stage.getStageNumber();
 447                                 status.getConfiguration().setToStage(n - 1);
 448                                 status.getFlightData().addEvent(event);
 449                                 break;
 450                         }
 451
 452                         case APOGEE:
 453                                 // Mark apogee as reached
 454                                 status.setApogeeReached(true);
 455                                 status.getFlightData().addEvent(event);
 456                                 break;
 457
 458                         case RECOVERY_DEVICE_DEPLOYMENT:
 459                                 RocketComponent c = event.getSource();
 460                                 int n = c.getStageNumber();
 461                                 // Ignore event if stage not active
 462                                 if (status.getConfiguration().isStageActive(n)) {
 463                                         // TODO: HIGH: Check stage activeness for other events as well?
 464
 465                                         // Check whether any motor in the active stages is active anymore
 466                                         for (MotorId motorId : status.getMotorConfiguration().getMotorIDs()) {
 467                                                 int stage = ((RocketComponent) status.getMotorConfiguration().
 468                                                                 getMotorMount(motorId)).getStageNumber();
 469                                                 if (!status.getConfiguration().isStageActive(stage))
 470                                                         continue;
 471                                                 if (!status.getMotorConfiguration().getMotorInstance(motorId).isActive())
 472                                                         continue;
 473                                                 status.getWarnings().add(Warning.RECOVERY_DEPLOYMENT_WHILE_BURNING);
 474                                         }
 475
 476                                         // Check for launch rod
 477                                         if (!status.isLaunchRodCleared()) {
 478                                                 status.getWarnings().add(Warning.fromString("Recovery device device deployed while on " +
 479                                                                 "the launch guide."));
 480                                         }
 481
 482                                         // Check current velocity
 483                                         if (status.getRocketVelocity().length() > 20) {
 484                                                 // TODO: LOW: Custom warning.
 485                                                 status.getWarnings().add(Warning.fromString("Recovery device deployment at high " +
 486                                                                 "speed ("
 487                                                                 + UnitGroup.UNITS_VELOCITY.toStringUnit(status.getRocketVelocity().length())
 488                                                                 + ")."));
 489                                         }
 490
 491                                         status.setLiftoff(true);
 492                                         status.getDeployedRecoveryDevices().add((RecoveryDevice) c);
 493
 494                                         this.currentStepper = this.landingStepper;
 495                                         this.status = currentStepper.initialize(status);
 496
 497                                         status.getFlightData().addEvent(event);
 498                                 }
 499                                 break;
 500
 501                         case GROUND_HIT:
 502                                 status.getFlightData().addEvent(event);
 503                                 break;
 504
 505                         case SIMULATION_END:
 506                                 ret = false;
 507                                 status.getFlightData().addEvent(event);
 508                                 break;
 509
 510                         case ALTITUDE:
 511                                 break;
 512                         }
 513
 514                 }
 515
 516
 517                 // If no motor has ignited, abort
 518                 if (!status.isMotorIgnited()) {
 519                         throw new MotorIgnitionException("No motors ignited.");
 520                 }
 521
 522                 return ret;
 523         }
 524
 525         /**
 526          * Add a flight event to the event queue unless a listener aborts adding it.
 527          *
 528          * @param event         the event to add to the queue.
 529          */
 530         private void addEvent(FlightEvent event) throws SimulationException {
 531                 if (SimulationListenerHelper.fireAddFlightEvent(status, event)) {
 532                         status.getEventQueue().add(event);
 533                 }
 534         }
 535
 536
 537
 538         /**
 539          * Return the next flight event to handle, or null if no more events should be handled.
 540          * This method jumps the simulation time forward in case no motors have been ignited.
 541          * The flight event is removed from the event queue.
 542          *
 543          * @param status        the simulation status
 544          * @return                      the flight event to handle, or null
 545          */
 546         private FlightEvent nextEvent() {
 547                 EventQueue queue = status.getEventQueue();
 548                 FlightEvent event = queue.peek();
 549                 if (event == null)
 550                         return null;
 551
 552                 // Jump to event if no motors have been ignited
 553                 if (!status.isMotorIgnited() && event.getTime() > status.getSimulationTime()) {
 554                         status.setSimulationTime(event.getTime());
 555                 }
 556                 if (event.getTime() <= status.getSimulationTime()) {
 557                         return queue.poll();
 558                 } else {
 559                         return null;
 560                 }
 561         }
 562
 563
 564
 565         private void checkNaN() throws SimulationException {
 566                 double d = 0;
 567                 boolean b = false;
 568                 d += status.getSimulationTime();
 569                 d += status.getPreviousTimeStep();
 570                 b |= status.getRocketPosition().isNaN();
 571                 b |= status.getRocketVelocity().isNaN();
 572                 b |= status.getRocketOrientationQuaternion().isNaN();
 573                 b |= status.getRocketRotationVelocity().isNaN();
 574                 d += status.getEffectiveLaunchRodLength();
 575
 576                 if (Double.isNaN(d) || b) {
 577                         log.error("Simulation resulted in NaN value:" +
 578                                         " simulationTime=" + status.getSimulationTime() +
 579                                         " previousTimeStep=" + status.getPreviousTimeStep() +
 580                                         " rocketPosition=" + status.getRocketPosition() +
 581                                         " rocketVelocity=" + status.getRocketVelocity() +
 582                                         " rocketOrientationQuaternion=" + status.getRocketOrientationQuaternion() +
 583                                         " rocketRotationVelocity=" + status.getRocketRotationVelocity() +
 584                                         " effectiveLaunchRodLength=" + status.getEffectiveLaunchRodLength());
 585                         throw new SimulationException("Simulation resulted in not-a-number (NaN) value, please report a bug.");
 586                 }
 587         }
 588
 589
 590 }