Op 28-06-11 11:23, Michael Anstis schreef:

Not completely understanding why solver.solve() would only run for 1ms,

It seems stupid indeed, but there are some cases:
- Cancellation: the user presses the "terminate early" button
- Cancellation: the whole system is going down (ctrl-c / kill)
- In real-time planning cases, the answer is needed NOW (even though we just started planning 1 or 10ms ago).
In that last case you'll probably still want to have an initialized solution and configure it appropriate to do random initialization (= really fast and really stupid) anyway.

So it looks like cancellation is the only real use case.
And I 'll support JBRULES-3105 "Planner: construction heuristics should be able to optionally ignore terminateEarly until a solution is initialized" in the future,
for the real-time planning case.

isn't a partially initialised starting solution a runtime error and (3) have solver.getBestSolution() throw a "SolutionsNotInitialisedException" an option?

Intresting idea. It should definitely not be a checked exception. Let's call this 3)

1) It returns null. So you 'll need to do null checks:
Solution bestSolution = solver.getBestSolution();
if (bestSolution == null) {
// ... do things with bestSolution
Score bestScore = bestSolution.getScore();
}

2) It returns the partially initialized solution. So you'll need to do
isBestSolutionInitialized checks:
Solution bestSolution = solver.getBestSolution();
if (solver.isBestSolutionInitialized()) {
// ... do things with bestSolution
Score bestScore = bestSolution.getScore();
}

3) it throws a SolutionUninitialisedException (runtime exception)
If you configured JBRULES-3105, then this works:
     Solution bestSolution = solver.getBestSolution();
     // ... do things with bestSolution
     Score bestScore = bestSolution.getScore();
Otherwise, you probably want to do this instead:
try {
     Solution bestSolution = solver.getBestSolution();
     // ... do things with bestSolution
     Score bestScore = bestSolution.getScore();
} catch (SolutionUninitialisedException e) {
    // ...
}

On 28 June 2011 10:18, Geoffrey De Smet <ge0ffrey.spam@gmail.com> wrote:

Normally you use Planner like this:

solver.solve()
Solution bestSolution = solver.getBestSolution();
// ... do things with bestSolution
Score bestScore = bestSolution.getScore();

But let's suppose we give it 1 millisecond to plan and use a big,
uninitialized starting solution
and our initialization algorithm actually terminates immediately as
requested.
It won't be able to completely initialize the solution in that case.
What should solver.getBestSolution() return in that case? null or the
partially initialized solution?

1) It returns null. So you 'll need to do null checks:
Solution bestSolution = solver.getBestSolution();
if (bestSolution == null) {
// ... do things with bestSolution
Score bestScore = bestSolution.getScore();
}

2) It returns the partially initialized solution. So you'll need to do
isBestSolutionInitialized checks:
Solution bestSolution = solver.getBestSolution();
if (solver.isBestSolutionInitialized()) {
// ... do things with bestSolution
Score bestScore = bestSolution.getScore();
}

What makes more sense?

--
With kind regards,
Geoffrey De Smet

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-- 
With kind regards,
Geoffrey De Smet