R: Compute a quadratic form

coxph.wtest {survival} | R Documentation

## Compute a quadratic form

### Description

This function is used internally by several survival routines. It computes a simple quadratic form, while properly dealing with missings.

### Usage

    coxph.wtest(var, b, toler.chol = 1e-09)

### Arguments

`var` | variance matrix
`b` | vector
`toler.chol` | tolerance for the internal cholesky decomposition

### Details

Compute b' V-inverse b. Equivalent to sum(b * solve(V,b)), except for the case of redundant covariates in the original model, which lead to NA values in V and b.

### Value

a real number

### Author(s)

Terry Therneau

[Package survival version 3.2-7 Index]