lasso2 (version 1.2-21.1)

# qr.rtr.inv: Reconstruct the Inverse of R'R from a QR Object

## Description

From a QR object, compute the inverse matrix which is implicitely (but not explicitly!) used to solve the underlying least squares problem.

## Usage

qr.rtr.inv(qr)

## Arguments

qr

\"qr\" object, typically resulting from qr(.).

## Value

The $$p \times p$$ matrix $$(R'R)^{-1}$$ or equivalently, the inverse of $$X'X$$ (i.e. t(X) %*% X in R).

qr, qr.R, backsolve.
# NOT RUN {