Fixed initial size threshold for over-approx.

src/storm-pomdp/modelchecker/ApproximatePOMDPModelchecker.cpp

@@ -250,7 +250,7 @@ namespace storm {
                     overApproximation = std::make_shared<ExplorerType>(overApproxBeliefManager, lowerPomdpValueBounds, upperPomdpValueBounds);
                     overApproxHeuristicPar.gapThreshold = options.gapThresholdInit;
                     overApproxHeuristicPar.observationThreshold = options.obsThresholdInit;
-                    overApproxHeuristicPar.sizeThreshold = options.sizeThresholdInit;
+                    overApproxHeuristicPar.sizeThreshold = options.sizeThresholdInit == 0 ? std::numeric_limits<uint64_t>::max() : options.sizeThresholdInit;
                     overApproxHeuristicPar.optimalChoiceValueEpsilon = options.optimalChoiceValueThresholdInit;
                     buildOverApproximation(targetObservations, min, rewardModelName.is_initialized(), false, overApproxHeuristicPar, observationResolutionVector, overApproxBeliefManager, overApproximation);
                     if (!overApproximation->hasComputedValues()) {