Le 16/08/10 09:35, Linda Eaton a écrit :
I am trying to get documentation about the random number generator used in
"sample". The help for sample does not mention it. Can anyone point me in
the right direction.
Thanks
Hi,
You can follow the white rabbit into the code burrow.
> sample
function (x, size, replace = FALSE, prob = NULL)
{
if (length(x) == 1L && is.numeric(x) && x >= 1) {
if (missing(size))
size <- x
.Internal(sample(x, size, replace, prob))
}
else {
if (missing(size))
size <- length(x)
x[.Internal(sample(length(x), size, replace, prob))]
}
}
<environment: namespace:base>
so you need to look for the internal sample, you can search for this in
the file src/main/names.c in the R source, you'll see that line :
{"sample", do_sample, 0, 11, 4, {PP_FUNCALL, PREC_FN,
0}},
Then you grep for do_sample in the src/main directory, which leads you
to the random.c file :
/* do_sample - probability sampling with/without replacement.
.Internal(sample(n, size, replace, prob))
*/
SEXP attribute_hidden do_sample(SEXP call, SEXP op, SEXP args, SEXP rho)
You'll have all the details there.
Romain
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Romain Francois
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