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Solving clustered low-rank semidefinite programs arising from polynomial optimization

Nando Leijenhorst, David de Laat

TL;DR

This work develops a high-precision primal-dual interior-point method that exploits clustered low-rank semidefinite constraints arising from sums-of-squares formulations of polynomial optimization problems in discrete geometry. By integrating sampling-based representations, symmetry reduction, and a greedy procedure for selecting good sample points and bases, the approach achieves substantial speedups and improved numerical stability over prior solvers. The authors implement a Julia-based solver with fast matrix multiplication and demonstrate the method on two core applications: the three-point kissing-number bound and the binary sphere packing bound, obtaining a 28x speedup in the kissing-number case and extending bounds to higher degrees and dimensions. These advances enable solving previously intractable high-degree instances, yielding improved bounds in dimensions $11$--$23$ and providing new insights into conditioning and convergence for matrix polynomial programs via clustered low-rank structure.

Abstract

We study a primal-dual interior point method specialized to clustered low-rank semidefinite programs requiring high precision numerics, which arise from certain multivariate polynomial (matrix) programs through sums-of-squares characterizations and sampling. We consider the interplay of sampling and symmetry reduction as well as a greedy method to obtain numerically good bases and sample points. We apply this to the computation of three-point bounds for the kissing number problem, for which we show a significant speedup. This allows for the computation of improved kissing number bounds in dimensions $11$ through $23$. The approach performs well for problems with bad numerical conditioning, which we show through new computations for the binary sphere packing problem.

Solving clustered low-rank semidefinite programs arising from polynomial optimization

TL;DR

This work develops a high-precision primal-dual interior-point method that exploits clustered low-rank semidefinite constraints arising from sums-of-squares formulations of polynomial optimization problems in discrete geometry. By integrating sampling-based representations, symmetry reduction, and a greedy procedure for selecting good sample points and bases, the approach achieves substantial speedups and improved numerical stability over prior solvers. The authors implement a Julia-based solver with fast matrix multiplication and demonstrate the method on two core applications: the three-point kissing-number bound and the binary sphere packing bound, obtaining a 28x speedup in the kissing-number case and extending bounds to higher degrees and dimensions. These advances enable solving previously intractable high-degree instances, yielding improved bounds in dimensions -- and providing new insights into conditioning and convergence for matrix polynomial programs via clustered low-rank structure.

Abstract

We study a primal-dual interior point method specialized to clustered low-rank semidefinite programs requiring high precision numerics, which arise from certain multivariate polynomial (matrix) programs through sums-of-squares characterizations and sampling. We consider the interplay of sampling and symmetry reduction as well as a greedy method to obtain numerically good bases and sample points. We apply this to the computation of three-point bounds for the kissing number problem, for which we show a significant speedup. This allows for the computation of improved kissing number bounds in dimensions through . The approach performs well for problems with bad numerical conditioning, which we show through new computations for the binary sphere packing problem.
Paper Structure (10 sections, 8 theorems, 69 equations, 6 figures, 1 table)

This paper contains 10 sections, 8 theorems, 69 equations, 6 figures, 1 table.

Key Result

Theorem 3.1

Let $f \in \mathbb{R}[x]^{m \times m}$ and $G\subseteq \mathbb{R}[x]$ finite. Suppose $\mathcal{M}(G)$ is Archimedean. If $f \succ 0$ on $\mathcal{S}(G)$, then $f \in \mathcal{M}(G)$.

Figures (6)

  • Figure 6.1: The time needed to compute the three-point bound for the kissing number in dimension $n=4$ for several degrees $d$ on a linear scale, using SDPA-GMP and ClusteredLowRankSolver.
  • Figure 6.2: The time needed to compute the three-point bound for the kissing number in dimension $n=4$ for several degrees $d$ on a log-log scale, using SDPA-GMP and ClusteredLowRankSolver.
  • Figure 6.3: The binary sphere packing bound in dimension $n=2$ and Florian's bound.
  • Figure 6.4: Binary sphere packing upper bounds in dimension $n=8$.
  • Figure 6.5: The binary sphere packing bound in dimension $24$. The dotted line is the maximum density of single sphere packings and the dashed line the optimal density when $r$ tends to $0$.
  • ...and 1 more figures

Theorems & Definitions (13)

  • Theorem 3.1: scherer_matrix_2006klep_pure_2010
  • Corollary 3.2
  • Lemma 3.3
  • proof
  • Proposition 4.1
  • proof
  • Proposition 4.2
  • proof
  • Lemma 4.3
  • proof
  • ...and 3 more