# coxph.wtest

From survival v3.1-8
by Terry Therneau

##### Compute a quadratic form

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

- Keywords
- survival

##### 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

*Documentation reproduced from package survival, version 3.1-8, License: LGPL (>= 2)*

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