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Bibliographic Details
Main Authors: Lindquist, Neil, Luszczek, Piotr, Dongarra, Jack
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2312.09376
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author Lindquist, Neil
Luszczek, Piotr
Dongarra, Jack
author_facet Lindquist, Neil
Luszczek, Piotr
Dongarra, Jack
contents Parker and Lê introduced random butterfly transforms (RBTs) as a preprocessing technique to replace pivoting in dense LU factorization. Unfortunately, their FFT-like recursive structure restricts the dimensions of the matrix. Furthermore, on multi-node systems, efficient management of the communication overheads restricts the matrix's distribution even more. To remove these limitations, we have generalized the RBT to arbitrary matrix sizes by truncating the dimensions of each layer in the transform. We expanded Parker's theoretical analysis to generalized RBT, specifically that in exact arithmetic, Gaussian elimination with no pivoting will succeed with probability 1 after transforming a matrix with full-depth RBTs. Furthermore, we experimentally show that these generalized transforms improve performance over Parker's formulation by up to 62\% while retaining the ability to replace pivoting. This generalized RBT is available in the SLATE numerical software library.
format Preprint
id arxiv_https___arxiv_org_abs_2312_09376
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Generalizing Random Butterfly Transforms to Arbitrary Matrix Sizes
Lindquist, Neil
Luszczek, Piotr
Dongarra, Jack
Numerical Analysis
65F05
G.1; G.4
Parker and Lê introduced random butterfly transforms (RBTs) as a preprocessing technique to replace pivoting in dense LU factorization. Unfortunately, their FFT-like recursive structure restricts the dimensions of the matrix. Furthermore, on multi-node systems, efficient management of the communication overheads restricts the matrix's distribution even more. To remove these limitations, we have generalized the RBT to arbitrary matrix sizes by truncating the dimensions of each layer in the transform. We expanded Parker's theoretical analysis to generalized RBT, specifically that in exact arithmetic, Gaussian elimination with no pivoting will succeed with probability 1 after transforming a matrix with full-depth RBTs. Furthermore, we experimentally show that these generalized transforms improve performance over Parker's formulation by up to 62\% while retaining the ability to replace pivoting. This generalized RBT is available in the SLATE numerical software library.
title Generalizing Random Butterfly Transforms to Arbitrary Matrix Sizes
topic Numerical Analysis
65F05
G.1; G.4
url https://arxiv.org/abs/2312.09376