Get a L'Ecuyer-CMRG seed either from an input seed or the current RNG state
Get a L'Ecuyer-CMRG seed either from an input seed or the current RNG state
as_lecyer_cmrg_seed(seed) is_lecyer_cmrg_seed(seed)
seed |
TRUE or NA, or a numeric vector of length one or seven. |
The as_lecyer_cmrg_seed() function preserves the current RNG state, that
is, it leaves globalenv()$.Random.seed intact, which means it also leaved
the RNG kind (RNGkind()) intact.
Per base::RNGkind(), a L'Ecuyer-CMRG seed comprise a length-seven integer
vector of format .Random.seed <- c(rng.kind, n) where length(n) == 6L and rng.kind fulfills rng.kind %% 10000L == 407L.
as_lecyer_cmrg_seed(seed) returns a L'Ecuyer-CMRG seed, which is a
7-digit integer vector, based on the input seed.
If already a L'Ecuyer-CMRG seed, then seed is return as-is.
If a scalar integer, then a random L'Ecuyer-CMRG seed is created based
on this seed as the current RNG state.
If seed = TRUE and the current seed is already a L'Ecuyer-CMRG seed,
then then current seed (.Random.seed) is return as-is.
If seed = TRUE and the current seed is not of the 'L'Ecuyer-CMRG' kind,
or seed = NA, then a random one is created (based on the current RNG
state).
Any other values, including FALSE, is an error.
is_lecyer_cmrg_seed(seed) returns TRUE if seed is L'Ecuyer-CMRG seed,
otherwise FALSE.
# The current RNG kind okind <- RNGkind() oseed <- globalenv()$.Random.seed # (a) A L'Ecuyer-CMRG seed based on a numeric-scalar seed seed1 <- future:::as_lecyer_cmrg_seed(42) str(seed1) ## int [1:7] 10407 -2133391687 507561766 1260545903 1362917092 -1772566379 -1344458670 # The RNG kind and the RNG state is preserved stopifnot( future:::is_lecyer_cmrg_seed(seed1), identical(RNGkind(), okind), identical(globalenv()$.Random.seed, oseed) ) # (b) A L'Ecuyer-CMRG seed based on a L'Ecuyer-CMRG seed seed2 <- future:::as_lecyer_cmrg_seed(seed1) str(seed2) ## int [1:7] 10407 -2133391687 507561766 1260545903 1362917092 -1772566379 -1344458670 # The input L'Ecuyer-CMRG seed is returned as-is stopifnot(identical(seed2, seed1)) # The RNG kind and the RNG state is preserved stopifnot( future:::is_lecyer_cmrg_seed(seed2), identical(RNGkind(), okind), identical(globalenv()$.Random.seed, oseed) ) # (c) A L'Ecuyer-CMRG seed based on the current RNG state seed3 <- future:::as_lecyer_cmrg_seed(TRUE) str(seed3) ## int [1:7] 10407 495333909 -1491719214 416071979 49340016 1956499377 899435966 stopifnot(future:::is_lecyer_cmrg_seed(seed3)) # All of the above calls preserve the RNG state including the RNG kind stopifnot( identical(RNGkind(), okind), identical(globalenv()$.Random.seed, oseed) )
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