Compute a quadratic form
This function is used internally by several survival routines. It computes a simple quadratic form, while properly dealing with missings.
coxph.wtest(var, b, toler.chol = 1e-09)
tolerance for the internal cholesky decomposition
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.
a real number