Question: Arguments for z in simEventData()

[tobiasmuetze]

First of all, this is an amazing versatile package. It is very useful, especially for simulating event data.

I am currently looking at the following example from this vignette.

zFun3 <- function(time, a, b) cbind(time / 10 + a, as.numeric(time > b))
(simDat <- simEventData(nProcess = 3, z = zFun3, zCoef = c(- 0.1, 0.5),
                        arguments = list(z = list(a = quote(rpois(1, 10) / 10),
                                                  b = quote(runif(1, 1, 3))))))

I was trying to modify this code to fix the values of a:

zFun3 <- function(time, a, b) cbind(time / 10 + a, as.numeric(time > b))
(simDat <- simEventData(nProcess = 3, z = zFun3, zCoef = c(- 0.1, 0.5),
                        arguments = list(z = list(a = c(0.1, 0.2, 0.3),
                                                  b = quote(runif(1, 1, 3))))))

However, this does not work. Any suggestions how to have different but deterministic values for inputs of z?

[wenjie2wang]

Thanks for the question. I do not have a good solution to it now. But the simEventData() is a simple wrapper function for the simEvent() function. Thus, a quick workaround can be as follows:

library(reda)

zFun3 <- function(time, a, b) cbind(time / 10 + a, as.numeric(time > b))

## workaround
set.seed(123)
a <- seq(0.1, by = 0.1, length.out = 3)
helper <- reda:::simEvent2data
simDat <- lapply(seq_along(a), function(i) {
    res <- simEvent(z = zFun3,
                    zCoef = c(- 0.1, 0.5),
                    arguments = list(
                        z = list(a = a[i],
                                 b = quote(runif(1, 1, 3)))))
    helper(ID = i, res)
}) |> do.call(rbind, args = _)

str(simDat)
#> 'data.frame':    13 obs. of  6 variables:
#>  $ ID    : int  1 1 1 1 1 1 1 1 2 2 ...
#>  $ time  : num  0.582 1.925 1.957 2.013 2.333 ...
#>  $ event : num  1 1 1 1 1 1 1 0 1 1 ...
#>  $ origin: num  0 0 0 0 0 0 0 0 0 0 ...
#>  $ X.1   : num  0.158 0.292 0.296 0.301 0.333 ...
#>  $ X.2   : num  0 1 1 1 1 1 1 1 0 0 ...
#>  - attr(*, "recurrent")= logi TRUE

## check the underlying "a"
with(simDat, cbind(ID, a = X.1 - time / 10))
#>       ID   a
#>  [1,]  1 0.1
#>  [2,]  1 0.1
#>  [3,]  1 0.1
#>  [4,]  1 0.1
#>  [5,]  1 0.1
#>  [6,]  1 0.1
#>  [7,]  1 0.1
#>  [8,]  1 0.1
#>  [9,]  2 0.2
#> [10,]  2 0.2
#> [11,]  2 0.2
#> [12,]  2 0.2
#> [13,]  3 0.3

^{Created on 2023-04-14 with reprex v2.0.2}

A note to myself: it seems that it would be helpful to have an internal variable such as process_id for each process to use.

[tobiasmuetze]

Thanks for your clarifications. I agree that it would be great extension to have a variable that is used for each process.