# coxph.wtest: 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.