Hi, @bcazabonne and all,
I’ve found a bug which leads to a memory leak, in tutorial.
I followed the orbit determination tutorial. It’s very wonderful, helping me starting to do an orbit determination.
Due to this GC overhead limit exceeded error, I google and google.
I tried to extract all java object in python following the previous mentioned topic. The error remains.
I noticed that someone says a WoW tool named VisualVM (https://visualvm.github.io/), which can be used to monitor the memory of VM. It’s really a powerful tool actually.
Here’s a dumped heap. We can see that there is a loop reference between lsBuilder and observer.
I checked the src of tutorial.
In the class org.orekit.tutorials.estimation.common.AbstractOrbitDetermination, new an org.orekit.tutorials.estimation.common.OrbitDeterminationObserver instance and set it as the estimator’s observer.
// Set the observer and estimate orbit
estimator.setObserver(new OrbitDeterminationObserver(initialGuess,
logStream,
estimator));
In the method setObserver of class org.orekit.estimation.leastsquares.BatchLSEstimator, the property observer is assigned. That is, the estimator refers to the observer.
/** Set an observer for iterations.
* @param observer observer to be notified at the end of each iteration
*/
public void setObserver(final BatchLSObserver observer) {
this.observer = observer;
}
And in the construct of class OrbitDeterminationObserver, the property estimator is assigned by the parameter estimator. That is, the observer refers to the estimator. A loop occurs.
public OrbitDeterminationObserver(final Orbit initialGuess,
final PrintStream logStream,
final BatchLSEstimator estimator) {
this.previousPV = initialGuess.getPVCoordinates();
this.logStream = logStream;
this.estimator = estimator;
String header = FORMAT_HEADER;
header = addParametersNames(header,
estimator.getOrbitalParametersDrivers(true),
estimator.getPropagatorParametersDrivers(true),
estimator.getMeasurementsParametersDrivers(true));
System.out.format(Locale.US, header);
if (logStream != null) {
logStream.format(Locale.US, header);
}
}
It does not matter in simple mode, or just one run orbit determination. For a massive batch orbit determination, it leads to memory out error.
The reference of observer to the estimator should be removed, by deleting the observer’s property estimator.