Output-Sparse Matrix Multiplication Using Compressed Sensing

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Bennett, Huck, Gajulapalli, Karthik, Golovnev, Alexander, Warton, Evelyn
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911105377370112
author Bennett, Huck
Gajulapalli, Karthik
Golovnev, Alexander
Warton, Evelyn
author_facet Bennett, Huck
Gajulapalli, Karthik
Golovnev, Alexander
Warton, Evelyn
contents We give two algorithms for output-sparse matrix multiplication (OSMM), the problem of multiplying two $n \times n$ matrices $A, B$ when their product $AB$ is promised to have at most $O(n^δ)$ many non-zero entries for a given value $δ\in [0, 2]$. We then show how to speed up these algorithms in the fully sparse setting, where the input matrices $A, B$ are themselves sparse. All of our algorithms work over arbitrary rings. Our first, deterministic algorithm for OSMM works via a two-pass reduction to compressed sensing. It runs in roughly $n^{ω(δ/2, 1, 1)}$ time, where $ω(\cdot, \cdot, \cdot)$ is the rectangular matrix multiplication exponent. This substantially improves on prior deterministic algorithms for output-sparse matrix multiplication. Our second, randomized algorithm for OSMM works via a reduction to compressed sensing and a variant of matrix multiplication verification, and runs in roughly $n^{ω(δ- 1, 1, 1)}$ time. This algorithm and its extension to the fully sparse setting have running times that match those of the (randomized) algorithms for OSMM and FSMM, respectively, in recent work of Abboud, Bringmann, Fischer, and Künnemann (SODA, 2024). Our algorithm uses different techniques and is arguably simpler. Finally, we observe that the running time of our randomized algorithm and the algorithm of Abboud et al. are optimal via a simple reduction from rectangular matrix multiplication.
format Preprint
id arxiv_https___arxiv_org_abs_2508_10250
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Output-Sparse Matrix Multiplication Using Compressed Sensing
Bennett, Huck
Gajulapalli, Karthik
Golovnev, Alexander
Warton, Evelyn
Data Structures and Algorithms
We give two algorithms for output-sparse matrix multiplication (OSMM), the problem of multiplying two $n \times n$ matrices $A, B$ when their product $AB$ is promised to have at most $O(n^δ)$ many non-zero entries for a given value $δ\in [0, 2]$. We then show how to speed up these algorithms in the fully sparse setting, where the input matrices $A, B$ are themselves sparse. All of our algorithms work over arbitrary rings. Our first, deterministic algorithm for OSMM works via a two-pass reduction to compressed sensing. It runs in roughly $n^{ω(δ/2, 1, 1)}$ time, where $ω(\cdot, \cdot, \cdot)$ is the rectangular matrix multiplication exponent. This substantially improves on prior deterministic algorithms for output-sparse matrix multiplication. Our second, randomized algorithm for OSMM works via a reduction to compressed sensing and a variant of matrix multiplication verification, and runs in roughly $n^{ω(δ- 1, 1, 1)}$ time. This algorithm and its extension to the fully sparse setting have running times that match those of the (randomized) algorithms for OSMM and FSMM, respectively, in recent work of Abboud, Bringmann, Fischer, and Künnemann (SODA, 2024). Our algorithm uses different techniques and is arguably simpler. Finally, we observe that the running time of our randomized algorithm and the algorithm of Abboud et al. are optimal via a simple reduction from rectangular matrix multiplication.
title Output-Sparse Matrix Multiplication Using Compressed Sensing
topic Data Structures and Algorithms
url https://arxiv.org/abs/2508.10250