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https://issues.apache.org/jira/browse/MATH-322?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phil Steitz closed MATH-322.
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> during ODE integration, the last event in a pair of very close event may not
> be detected
> ----------------------------------------------------------------------------------------
>
> Key: MATH-322
> URL: https://issues.apache.org/jira/browse/MATH-322
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 2.0
> Environment: All
> Reporter: Luc Maisonobe
> Assignee: Luc Maisonobe
> Fix For: 2.1
>
>
> When an events follows a previous one very closely, it may be ignored. The
> occurrence of the bug depends on the side of the bracketing interval that was
> selected. For example consider a switching function that is increasing around
> first event around t = 90, reaches its maximum and is decreasing around the
> second event around t = 135. If an integration step spans from 67.5 and
> 112.5, the switching function values at start and end of step will have
> opposite signs, so the first event will be detected. The solver will find the
> event really occurs at 90.0 and will therefore truncate the step at 90.0. The
> next step will start from where the first step ends, i.e. it will start at
> 90.0. Let's say this step spans from 90.0 to 153.0. The switching function
> switches once again in this step.
> If the solver for the first event converged to a value slightly before 90.0
> (say 89.9999999), then the switch will not be detected because g(89.9999999)
> and g(153.0) are both negative.
> This bug was introduced as of r781157 (2009-06-02) when special handling of
> events very close to step start was added.
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