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RNG.R
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RNG.R
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#' @useDynLib batchtools next_streams
RNGStream = R6Class("RNGStream",
public = list(
start.seed = NA_integer_,
initialize = function(seed) {
prev.state = get0(".Random.seed", .GlobalEnv)
prev.rng = RNGkind()[1L]
on.exit({ RNGkind(prev.rng); assign(".Random.seed", prev.state, envir = .GlobalEnv) })
RNGkind("L'Ecuyer-CMRG")
set.seed(seed)
self$start.seed = get0(".Random.seed", .GlobalEnv)
assertInteger(self$start.seed, len = 7L, any.missing = FALSE)
if (self$start.seed[1L] %% 100L != 7L)
stop("Invalid value of 'seed'")
},
get = function(i) {
i = asInteger(i, lower = 1, any.missing = FALSE)
x = .Call(next_streams, self$start.seed, as.integer(max(i)))
x[, i, drop = FALSE]
}
)
)
getSeed = function(start.seed, id) {
if (id > .Machine$integer.max - start.seed)
start.seed - .Machine$integer.max + id
else
start.seed + id
}
with_seed = function(seed, expr) {
if (!is.null(seed)) {
if (!exists(".Random.seed", .GlobalEnv))
set.seed(NULL)
state = get(".Random.seed", .GlobalEnv)
set.seed(seed)
on.exit(assign(".Random.seed", state, envir = .GlobalEnv))
}
eval.parent(expr)
}
if (FALSE) {
rng = RNGStream$new(123L)
i = 1:5e6
d = data.table(i = i, state = unname(as.list(as.data.frame(rng$get(i)))))
print(object.size(d), unit = "Mb")
system.time(rng$get(10000000))
}