MOA is an open source framework for Big Data stream mining. It includes a collection of machine learning algorithms (classification, regression, clustering, outlier detection, concept drift detection and recommender systems) and tools for evaluation.
Check line 135 of BasicClassificationPerformanceEvaluator, changed by the referred commit, to see one example of that kind of call: precision[i].add(Double.NaN).
That method is not able to receive Double.NaN values, but since commit f83f9afa722b898161a353f083d3e18c43243375, this situation can happens.
Check line 135 of BasicClassificationPerformanceEvaluator, changed by the referred commit, to see one example of that kind of call: precision[i].add(Double.NaN).