Efficient improved algorithms solve Beck Fiala problem for bounded sets

Improved Algorithms for Beck--Fiala with Bounded Sets

Data Structures and AlgorithmsDiscrete Mathematics

Summary

The Beck–Fiala problem involves splitting items into two groups so that the groups stay well balanced across many overlapping sets, especially when each item belongs to only a few sets. The authors present a better, faster algorithm to find such a balanced partition when each set includes only a limited number of items. Their method improves how closely balanced the groups can be, depending on the size and overlap of sets. They build upon previous algorithms to achieve these improvements effectively.

What this means in practice

A theory result. No direct application yet.

Authors

Dylan J. Altschuler

Abstract

We give an efficient algorithm with improved algorithmic guarantees for the (offline) Beck--Fiala problem when the sets have bounded size. Let $A$ be an arbitrary matrix $A\in\{0,1\}^{m\times n}$ with at most $d$ ones per column and at most $s$ ones per row. Let $\log^*$ denote the iterated logarithm and $\ell_j$ denote the $j$-fold composition of log. Assume $s\le\exp(O(\sqrt d))$. We provide an efficient algorithm that, for arbitrary sparsity $d$, gives $O(\sqrt d(1+\log^*n))$ discrepancy. Moreover, if $d\ge\ell_j(n)$ for a fixed integer $j\ge1$, the algorithm gives $O_j(\sqrt d)$ discrepancy. The proof is a bootstrapping scheme using the Bansal-Jiang algorithm.