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second attempt at fixing MATH-484 

This fixes bad behavior when several events occur during a long step
This also fixes bad behavior when events are triggered during backward integration
Jira: MATH-484

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1070499 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Luc Maisonobe 2011-02-14 14:19:55 +00:00
parent 26c1c29575
commit 5a2bf9c657
1 changed files with 20 additions and 8 deletions
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28
src/main/java/org/apache/commons/math/ode/AbstractIntegrator.java
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@ -21,6 +21,7 @@ import java.util.ArrayList;
import java.util.Collection; import java.util.Collection;
import java.util.Collections; import java.util.Collections;
import java.util.Comparator; import java.util.Comparator;
import java.util.Iterator;
import java.util.List; import java.util.List;
import java.util.SortedSet; import java.util.SortedSet;
import java.util.TreeSet; import java.util.TreeSet;
@ -245,16 +246,17 @@ public abstract class AbstractIntegrator implements FirstOrderIntegrator {
statesInitialized = true; statesInitialized = true;
} }
// search for next events that may occur during the step
final int orderingSign = interpolator.isForward() ? +1 : -1;
SortedSet<EventState> occuringEvents = new TreeSet<EventState>(new Comparator<EventState>() { SortedSet<EventState> occuringEvents = new TreeSet<EventState>(new Comparator<EventState>() {
/** {@inheritDoc} */ /** {@inheritDoc} */
public int compare(EventState es0, EventState es1) { public int compare(EventState es0, EventState es1) {
return Double.compare(es0.getEventTime(), es1.getEventTime()); return orderingSign * Double.compare(es0.getEventTime(), es1.getEventTime());
} }
}); });
// find all events that occur during the step
for (final EventState state : eventsStates) { for (final EventState state : eventsStates) {
if (state.evaluateStep(interpolator)) { if (state.evaluateStep(interpolator)) {
// the event occurs during the current step // the event occurs during the current step
@ -262,19 +264,23 @@ public abstract class AbstractIntegrator implements FirstOrderIntegrator {
} }
} }
// handle the events chronologically while (!occuringEvents.isEmpty()) {
for (final EventState state : occuringEvents) {
// handle the chronologically first event
final Iterator<EventState> iterator = occuringEvents.iterator();
final EventState currentEvent = iterator.next();
iterator.remove();
// restrict the interpolator to the first part of the step, up to the event // restrict the interpolator to the first part of the step, up to the event
final double eventT = state.getEventTime(); final double eventT = currentEvent.getEventTime();
interpolator.setSoftPreviousTime(previousT); interpolator.setSoftPreviousTime(previousT);
interpolator.setSoftCurrentTime(eventT); interpolator.setSoftCurrentTime(eventT);
// trigger the event // trigger the event
interpolator.setInterpolatedTime(eventT); interpolator.setInterpolatedTime(eventT);
final double[] eventY = interpolator.getInterpolatedState(); final double[] eventY = interpolator.getInterpolatedState();
state.stepAccepted(eventT, eventY); currentEvent.stepAccepted(eventT, eventY);
isLastStep = state.stop(); isLastStep = currentEvent.stop();
// handle the first part of the step, up to the event // handle the first part of the step, up to the event
for (final StepHandler handler : stepHandlers) { for (final StepHandler handler : stepHandlers) {
@ -287,7 +293,7 @@ public abstract class AbstractIntegrator implements FirstOrderIntegrator {
return eventT; return eventT;
} }
if (state.reset(eventT, eventY)) { if (currentEvent.reset(eventT, eventY)) {
// some event handler has triggered changes that // some event handler has triggered changes that
// invalidate the derivatives, we need to recompute them // invalidate the derivatives, we need to recompute them
System.arraycopy(eventY, 0, y, 0, y.length); System.arraycopy(eventY, 0, y, 0, y.length);
@ -301,6 +307,12 @@ public abstract class AbstractIntegrator implements FirstOrderIntegrator {
interpolator.setSoftPreviousTime(eventT); interpolator.setSoftPreviousTime(eventT);
interpolator.setSoftCurrentTime(currentT); interpolator.setSoftCurrentTime(currentT);
// check if the same event occurs again in the remaining part of the step
if (currentEvent.evaluateStep(interpolator)) {
// the event occurs during the current step
occuringEvents.add(currentEvent);
}
} }
interpolator.setInterpolatedTime(currentT); interpolator.setInterpolatedTime(currentT);