Multiplying and Factoring Matrices

All of us learn and teach matrix multiplication using rows times columns. Those inner products are the entries of AB. But to go backward-to factor a matrix into triangular or orthogonal or diagonal matrices-outer products are much better. Now AB is the sum of columns of A times rows of B: rank one m...

Full description

Bibliographic Details
Main Author: Strang, W. Gilbert (Author)
Other Authors: Massachusetts Institute of Technology. Department of Mathematics (Contributor)
Format: Article
Language:English
Published: Informa UK Limited, 2020-07-15T21:07:02Z.
Subjects:
Online Access:Get fulltext
LEADER 01086 am a22001693u 4500
001 126212
042 |a dc 
100 1 0 |a Strang, W. Gilbert  |e author 
100 1 0 |a Massachusetts Institute of Technology. Department of Mathematics  |e contributor 
245 0 0 |a Multiplying and Factoring Matrices 
260 |b Informa UK Limited,   |c 2020-07-15T21:07:02Z. 
856 |z Get fulltext  |u https://hdl.handle.net/1721.1/126212 
520 |a All of us learn and teach matrix multiplication using rows times columns. Those inner products are the entries of AB. But to go backward-to factor a matrix into triangular or orthogonal or diagonal matrices-outer products are much better. Now AB is the sum of columns of A times rows of B: rank one matrices. Our goal is to produce those columns and rows as simply as possible for A = LU (elimination) and A = CE (echelon form) and A = QR (Gram-Schmidt). Diagonalization by eigenvectors and by singular vectors is also expressed by columns times rows. 
546 |a en 
655 7 |a Article 
773 |t 10.1080/00029890.2018.1408378 
773 |t The American mathematical monthly