DHARMa (version 0.4.1)

getRandomState: Record and restore a random state

Description

The aim of this function is to record, manipulate and restore a random state

Usage

getRandomState(seed = NULL)

Arguments

seed

seed argument to set.seed(), typically a number. Additional options: NULL = no seed is set, but return includes function for restoring random seed. F = function does nothing, i.e. neither seed is changed, nor does the returned function do anything

Value

a list with various infos about the random state that after function execution, as well as a function to restore the previous state before the function execution

Details

This function is intended for two (not mutually exclusive tasks)

a) record the current random state

b) change the current random state in a way that the previous state can be restored

Examples

# NOT RUN {
set.seed(13)
runif(1)

# testing the function in standard settings
currentSeed = .Random.seed
x = getRandomState(123)
runif(1)
x$restoreCurrent()
all(.Random.seed == currentSeed)

# if no seed was set in env, this will also be restored

rm(.Random.seed) # now, there is no random seed
x = getRandomState(123)
exists(".Random.seed")  # TRUE
runif(1)
x$restoreCurrent()
exists(".Random.seed") # False
runif(1) # re-create a seed

# with seed = false 
currentSeed = .Random.seed
x = getRandomState(FALSE)
runif(1)
x$restoreCurrent()
all(.Random.seed == currentSeed)

# with seed = NULL 
currentSeed = .Random.seed
x = getRandomState(NULL)
runif(1)
x$restoreCurrent()
all(.Random.seed == currentSeed)
# }