RNG version

Change the RNG version and restore it afterwards.

with_rng_version(version, code)

local_rng_version(version, .local_envir = parent.frame())

Arguments

version

[character(1)] an R version number, e.g. "3.5.0", to switch to the RNG this version of R uses. See RNGversion().

code

[any]
Code to execute in the temporary environment

.local_envir

The environment to apply the change to.

Value

[any]
The results of the evaluation of the code argument.

Details

with_rng_version() runs the code with the specified RNG version and resets it afterwards.

local_rng_version() changes the RNG version for the caller execution environment.

See also

withr for examples

RNGversion(), RNGkind(), with_seed().

Examples

RNGkind()
#> [1] "Mersenne-Twister" "Inversion"        "Rejection"       
with_rng_version("3.0.0", RNGkind())
#> [1] "Mersenne-Twister" "Inversion"        "Rounding"        
with_rng_version("1.6.0", RNGkind())
#> [1] "Marsaglia-Multicarry"   "Buggy Kinderman-Ramage" "Rounding"              

with_rng_version("3.0.0",
  with_seed(42, sample(1:100, 3)))
#> [1] 92 93 29

with_rng_version("1.6.0",
  with_seed(42, sample(1:100, 3)))
#> Warning: buggy version of Kinderman-Ramage generator used
#> Warning: RNGkind: Marsaglia-Multicarry has poor statistical properties
#> [1] 33 44 32

RNGkind()
#> [1] "Mersenne-Twister" "Inversion"        "Rejection"       

fun1 <- function() {
  local_rng_version("3.0.0")
  with_seed(42, sample(1:100, 3))
}

fun2 <- function() {
  local_rng_version("1.6.0")
  with_seed(42, sample(1:100, 3))
}

RNGkind()
#> [1] "Mersenne-Twister" "Inversion"        "Rejection"       
fun1()
#> [1] 92 93 29
fun2()
#> Warning: buggy version of Kinderman-Ramage generator used
#> Warning: RNGkind: Marsaglia-Multicarry has poor statistical properties
#> [1] 33 44 32
RNGkind()
#> [1] "Mersenne-Twister" "Inversion"        "Rejection"