cgr_helper_mat_2: Continuous time Generalized Rapid response CUSUM (CGR-CUSUM)...
In cgrcusum: Continuous Time Generalized Rapid Response CUSUM

Description Usage Arguments Value Author(s) See Also Examples

This function calculates the value of the CGR-CUSUM using a matrix formulation of the problem - this can require a lot of available RAM.

1	cgr_helper_mat_2(data, ctimes, coxphmod, cbaseh, displaypb = FALSE)

`data`	`data.frame` containing the following named columns: `entrytime` numeric - time of entry into study, `otime` numeric - time from entry until event, `censorid` integer - (optional) censoring indicator (0 = right censored, 1 = observed), and optionally additional covariates used for risk-adjustment.
`ctimes`	(optional) vector of construction times at which the value of the chart should be determined. When not specified, the chart is constructed at all failure times.
`coxphmod`	(optional) a cox proportional hazards regression model as produced by the function `coxph()`. Standard practice: `coxph(Surv(survtime, censorid) ~ covariates, data = data)`. Alternatively, a list with: $formula (~ covariates) $coefficients (named vector specifying risk adjustment coefficients for covariates - names must be the same as in $formula and colnames of `data`).
`cbaseh`	a function which returns the non risk-adjusted cumulative baseline hazard H_0(t). If `cbaseh` is missing but `coxphmod` has been specified as a survival object, this baseline hazard rate will be determined using the provided `coxphmod`.
`displaypb`	boolean Display a progress bar?

A matrix with 4 named columns:

$time time at which the value of the CGR-CUSUM was determined
$value value at corresponding time of the CGR-CUSUM
$exp_theta_t value at corresponding time of the MLE θ_t
$S_nu time from which individuals contribute to the chart S_ν

Daniel Gomon

cgrcusum

## Not run: 
require(survival)
tdat <- subset(surgerydat, Hosp_num == 1)
tdat$otime <- tdat$entrytime + tdat$survtime
tcbaseh <- function(t) chaz_exp(t, lambda = 0.01)
varsanalysis <- c("age", "sex", "BMI")
exprfit <- as.formula(paste("Surv(survtime, censorid) ~" ,paste(varsanalysis, collapse='+')))
tcoxmod <- coxph(exprfit, data= surgerydat)
#Alternatively, cbaseh can be left empty when specifying coxphmod through coxph()
cgr2 <- cgr_helper_mat_2(data = tdat, ctimes = unique(tdat$entrytime + tdat$survtime),
                         coxphmod = tcoxmod, cbaseh = tcbaseh, displaypb = TRUE)

## End(Not run)