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https://issues.apache.org/jira/browse/MATH-811?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13464732#comment-13464732
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Yannick TANGUY commented on MATH-811:
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Hello Luc,
Ok, but could you explain a little bit please ?
As I understand the code, this value is true when g0 > 0, and is updated in
stepAccepted method. There's no getter for this value, and it's only used once
in the test "if (g0Positive ^ (gb >= 0))", so I guess it could be replaced by a
test on ga.
One thing I don't understand (and it may be the point you notice in the comment
"Simulated sign of g0 (we cheat when crossing events)." is the following code
in stepAccepted :
{noformat}
if (pendingEvent && (FastMath.abs(pendingEventTime - t) <=
convergence)) {
// force the sign to its value "just after the event"
previousEventTime = t;
g0Positive = increasing;
nextAction = handler.eventOccurred(t, y, !(increasing ^
forward));
} else {
g0Positive = g0 >= 0;
nextAction = EventHandler.Action.CONTINUE;
}
{noformat}
-> the value "increasing" relates to g function, and not to g0 value.
If removing g0positive field is a problem, we could put it again, but I don't
understand the reasons yet.
> Improve event detection by selecting g function slope
> -----------------------------------------------------
>
> Key: MATH-811
> URL: https://issues.apache.org/jira/browse/MATH-811
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: 3.1
> Reporter: Yannick TANGUY
> Attachments: JIRA-811_slope_selection.patch,
> JIRA-811_slope_selection_V2.patch, JIRA-811_slope_selection_with_spaces.patch
>
>
> We would like to select g function slope in CommonsMath event detection
> feature.
> This would improve event detection for the final user (the possibility to
> ignore some events, and less computation time) and also correct a bug found
> while using OREKIT (see https://www.orekit.org/forge/issues/104) in our
> applications.
> The modification consists in adding a method (getSlopeSelection() : int) in
> EventHandler, and modifying one conditionnal in the method evaluateStep
> (class EventState).
> We can provide modified code and unitary tests for this feature.
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