O'Reilly logo

Mastering Scientific Computing with R by Radia M. Johnson, Paul Gerrard

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Matrix decomposition

Matrix decomposition is the matrix equivalent to algebraic factorization. In this section, we will discuss methods that break a single matrix into the product of two or more smaller matrices.

QR decomposition

QR decomposition is a decomposition that breaks a matrix M into two different matrices, Q and R, such that M is equal to QR. Q is an orthogonal matrix (a matrix in which the inverse of the matrix is equal to its transposition), and R is an upper triangular matrix. Here, we demonstrate QR factorization in R on R's internal trees dataset using the qr command:

> data(trees) > head(trees) Girth Height Volume 1 8.3 70 10.3 2 8.6 65 10.3 3 8.8 63 10.2 4 10.5 72 16.4 5 10.7 81 18.8 6 10.8 83 19.7 > trees.qr <- qr(trees[,c(2:3)]) ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required