/** * Cuts a tree into several groups by specifying the desired number. * @param k the number of clusters. * @return the cluster label of each sample. */ public int[] partition(int k) { int n = merge.length + 1; int[] membership = new int[n]; IntHeapSelect heap = new IntHeapSelect(k); for (int i = 2; i <= k; i++) { heap.add(merge[n - i][0]); heap.add(merge[n - i][1]); } for (int i = 0; i < k; i++) { bfs(membership, heap.get(i), i); } return membership; }
/** * Sort the smallest values. */ public void sort() { if (!sorted) { sort(heap, Math.min(k,n)); sorted = true; } }
/** * Assimilate a new value from the stream. */ public void add(int datum) { sorted = false; if (n < k) { heap[n++] = datum; if (n == k) { heapify(heap); } } else { n++; if (datum < heap[0]) { heap[0] = datum; SortUtils.siftDown(heap, 0, k-1); } } }
/** * Returns the i-<i>th</i> smallest value seen so far. i = 0 returns the smallest * value seen, i = 1 the second largest, ..., i = k-1 the last position * tracked. Also, i must be less than the number of previous assimilated. */ public int get(int i) { if (i > Math.min(k, n) - 1) { throw new IllegalArgumentException("HeapSelect i is greater than the number of data received so far."); } if (i == k-1) { return heap[0]; } if (!sorted) { sort(heap, Math.min(k,n)); sorted = true; } return heap[k-1-i]; }