MPI-I-98-1-002

Comparator networks for constructing binary heaps of size $n$ are presented which have size $O(n\log\log n)$ and depth $O(\log n)$. A lower bound of $n\log\log n-O(n)$ for the size of any heap construction network is also proven, implying that the networks presented are within a constant factor of optimal. We give a tight relation between the leading constants in the size of selection networks and in the size of heap constructiion networks.