Description Jan-Frederik Wigger 2011-11-14 04:17:15 EST

Created attachment 206928 [details]
a toy scenario producing the error message

During the simulation, an error message dialog pops up:

An internal error occured during: "Finite Difference Worker 1".

The corresponing console log message is:

!ENTRY org.eclipse.core.jobs 4 2 2011-11-14 10:12:10.952
!MESSAGE An internal error occurred during: "Finite Difference Worker 1".
!STACK 0
java.util.ConcurrentModificationException
	at org.eclipse.emf.common.util.AbstractEList$EIterator.checkModCount(AbstractEList.java:762)
	at org.eclipse.emf.common.util.AbstractEList$EIterator.doNext(AbstractEList.java:716)
	at org.eclipse.emf.common.util.AbstractEList$EIterator.next(AbstractEList.java:696)
	at org.eclipse.stem.diseasemodels.standard.impl.StandardDiseaseModelImpl.applyExternalDeltas(StandardDiseaseModelImpl.java:327)
	at org.eclipse.stem.solvers.fd.impl.FiniteDifferenceImpl.computeDeltasStep(FiniteDifferenceImpl.java:260)
	at org.eclipse.stem.solvers.fd.impl.FdJob.run(FdJob.java:63)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)




You already taught me how to avoid this:
-> set the number of worker threads to 1 (Window->Preferences STEM->Solver then "Number of concurrent worker threads").

and what's causing it:
The problem is really how we determine which nodes a thread updates, especially in a case when you have population models that only works on a single node.