  In this paper, we propose HyperFlowCutter, an algorithm for balanced
hypergraph bipartitioning. It is based on minimum S-T hyperedge cuts and
maximum flows. It computes a sequence of bipartitions that optimize cut size
and balance in the Pareto sense, being able to trade one for the other.
HyperFlowCutter builds on the FlowCutter algorithm for partitioning graphs. We
propose additional features, such as handling disconnected hypergraphs, novel
methods for obtaining starting S,T pairs as well as an approach to refine a
given partition with HyperFlowCutter. Our main contribution is ReBaHFC, a new
algorithm which obtains an initial partition with the fast multilevel
hypergraph partitioner PaToH and then improves it using HyperFlowCutter as a
refinement algorithm. ReBaHFC is able to significantly improve the solution
quality of PaToH at little additional running time. The solution quality is
only marginally worse than that of the best-performing hypergraph partitioners
KaHyPar and hMETIS, while being one order of magnitude faster. Thus ReBaHFC
offers a new time-quality trade-off in the current spectrum of hypergraph
partitioners. For the special case of perfectly balanced bipartitioning, only
the much slower plain HyperFlowCutter yields slightly better solutions than
ReBaHFC, while only PaToH is faster than ReBaHFC.
