Which formulas have you used in simmer.plot for displaying statistics

[ValerCheck]

Hi there.

I have followed through the simmer.plot code for displaying resources usage or utilization and I'm interested in the formulas you have used in calculations. I couldn't find any references to some scientific papers or books, articles which could shed the light on the usage of implemented formulas :)

For example for usage:

mean = c(0, cumsum(utils::head(.data$value, -1) * diff(.data$time))) / .data$time

or for utilization:

utilization = sum(.data$in_use, na.rm = TRUE) / sum(.data$dt, na.rm=TRUE)

I am just trying to understand the nature of those values but without some explanation it is a bit complicated. Thanks in advance.

[Enchufa2]

For example for usage:

mean = c(0, cumsum(utils::head(.data$value, -1) * diff(.data$time))) / .data$time

This is a cumulative weighted mean. For each t, we compute the average up to this t weighted by the duration of each observation.

or for utilization:

utilization = sum(.data$in_use, na.rm = TRUE) / sum(.data$dt, na.rm=TRUE)

And this is a simple weighted mean. The quotient server / capacity (the instantaneous utilization) is weighted again by the duration of each observation, and averaged. This one is a bit more complicated because, when a resource is closed (capacity < server), we take server as the capacity (and thus, the utilization is considered to be 100%); and in the special case in which capacity is 0, we set dt = 0 to avoid an Inf there.

[ValerCheck]

Thanks, will study it further :)