question: private double computeStopDistance ( List < KNNHeap > heaps ) { double pr_knn_distance = Double . NaN ; for ( KNNHeap knnList : heaps ) { double kdist = knnList . getKNNDistance ( ) ; pr_knn_distance = ( kdist < pr_knn_distance ) ? pr_knn_distance : kdist ; } if ( pr_knn_distance != pr_knn_distance ) { return Double . POSITIVE_INFINITY ; } return pr_knn_distance ; }
target:  Compute the maximum stop distance.