Examples with EventState org.orekit.propagation.events.EventState used on opensource projects

Example 1 with EventState

use of org.orekit.propagation.events.EventState in project Orekit by CS-SI.

the class AbstractAnalyticalPropagator method acceptStep.

/**
 * Accept a step, triggering events and step handlers.
 * @param interpolator interpolator for the current step
 * @param target final propagation time
 * @param epsilon threshold for end date detection
 * @return state at the end of the step
 * @exception OrekitException if the switching function cannot be evaluated
 * @exception MathRuntimeException if an event cannot be located
 */
protected SpacecraftState acceptStep(final OrekitStepInterpolator interpolator, final AbsoluteDate target, final double epsilon) throws OrekitException, MathRuntimeException {
    SpacecraftState previous = interpolator.getPreviousState();
    final SpacecraftState current = interpolator.getCurrentState();
    // initialize the events states if needed
    if (!statesInitialized) {
        if (!eventsStates.isEmpty()) {
            // initialize the events states
            for (final EventState<?> state : eventsStates) {
                state.reinitializeBegin(interpolator);
            }
        }
        statesInitialized = true;
    }
    // search for next events that may occur during the step
    final int orderingSign = interpolator.isForward() ? +1 : -1;
    final Queue<EventState<?>> occurringEvents = new PriorityQueue<>(new Comparator<EventState<?>>() {

        /**
         * {@inheritDoc}
         */
        @Override
        public int compare(final EventState<?> es0, final EventState<?> es1) {
            return orderingSign * es0.getEventDate().compareTo(es1.getEventDate());
        }
    });
    for (final EventState<?> state : eventsStates) {
        if (state.evaluateStep(interpolator)) {
            // the event occurs during the current step
            occurringEvents.add(state);
        }
    }
    OrekitStepInterpolator restricted = interpolator;
    do {
        eventLoop: while (!occurringEvents.isEmpty()) {
            // handle the chronologically first event
            final EventState<?> currentEvent = occurringEvents.poll();
            // get state at event time
            SpacecraftState eventState = restricted.getInterpolatedState(currentEvent.getEventDate());
            // try to advance all event states to current time
            for (final EventState<?> state : eventsStates) {
                if (state != currentEvent && state.tryAdvance(eventState, interpolator)) {
                    // we need to handle another event first
                    // remove event we just updated to prevent heap corruption
                    occurringEvents.remove(state);
                    // add it back to update its position in the heap
                    occurringEvents.add(state);
                    // re-queue the event we were processing
                    occurringEvents.add(currentEvent);
                    continue eventLoop;
                }
            }
            // all event detectors agree we can advance to the current event time
            final EventOccurrence occurrence = currentEvent.doEvent(eventState);
            final Action action = occurrence.getAction();
            isLastStep = action == Action.STOP;
            if (isLastStep) {
                // ensure the event is after the root if it is returned STOP
                // this lets the user integrate to a STOP event and then restart
                // integration from the same time.
                eventState = interpolator.getInterpolatedState(occurrence.getStopDate());
                restricted = restricted.restrictStep(previous, eventState);
            }
            // handle the first part of the step, up to the event
            if (getStepHandler() != null) {
                getStepHandler().handleStep(restricted, isLastStep);
            }
            if (isLastStep) {
                // the event asked to stop integration
                return eventState;
            }
            if (action == Action.RESET_DERIVATIVES || action == Action.RESET_STATE) {
                // some event handler has triggered changes that
                // invalidate the derivatives, we need to recompute them
                final SpacecraftState resetState = occurrence.getNewState();
                if (resetState != null) {
                    resetIntermediateState(resetState, interpolator.isForward());
                    return resetState;
                }
            }
            // at this point we know action == Action.CONTINUE
            // prepare handling of the remaining part of the step
            previous = eventState;
            restricted = new BasicStepInterpolator(restricted.isForward(), eventState, current);
            // check if the same event occurs again in the remaining part of the step
            if (currentEvent.evaluateStep(restricted)) {
                // the event occurs during the current step
                occurringEvents.add(currentEvent);
            }
        }
        // another event detector.
        for (final EventState<?> state : eventsStates) {
            if (state.tryAdvance(current, interpolator)) {
                occurringEvents.add(state);
            }
        }
    } while (!occurringEvents.isEmpty());
    isLastStep = target.equals(current.getDate());
    // handle the remaining part of the step, after all events if any
    if (getStepHandler() != null) {
        getStepHandler().handleStep(interpolator, isLastStep);
    }
    return current;
}