The Multinomial Distribution, Using Multiple Draws

Density function random generation for the multinomial distribution, modified to work with rvecs.

Usage

dmultinom_rvec(x, size = NULL, prob, log = FALSE)

rmultinom_rvec(n, size, prob, n_draw = NULL)

Arguments

x: Quantiles. Can be an rvec.
size: Total number of trials. See stats::dmultinom(). Can be an rvec.
prob: Numeric non-negative vector, giving the probability of each outcome. Internally normalized to sum to 1. See stats::dmultinom(). Can be an rvec.
log: Whether to return log(p) rather than p. Default is FALSE. Cannot be an rvec.
n: The length of random vector being created. Cannot be an rvec.
n_draw: Number of random draws in the random vector being created. Cannot be an rvec.

Value

dmultinom()
- If any of the arguments are rvecs, or if a value for n_draw is supplied, then an rvec
- Otherwise an ordinary R vector.
rmultinom()
- If n is 1, an rvec or ordinary R vector.
- If n is greater than 1, a list of rvecs or ordinary R vectors
rmultinom_rvec() always returns doubles (not integers).

Details

Functions dmultinom_rvec()and rmultinom_rvec() work like base R functions dmultinom() and rmultinom(), except that they accept rvecs as inputs. If any input is an rvec, then the output will be too. Function rmultinom_rvec() also returns an rvec if a value for n_draw is supplied.

Like the base R functions dmultinom() and [rmultinom(), dmultinom_rvec() and rmultinom_rvec() do not recycle their arguments.

Warning

From version rvec version 0.7.4 onwards, rmultinom_rvec() always returns doubles (not integers).

Examples

x <- rvec(list(c(1, 4, 0),
               c(1, 0, 0),
               c(1, 0, 0),
               c(1, 0, 4)))
prob <- c(1/4, 1/4, 1/4, 1/4)
dmultinom_rvec(x = x, prob = prob)
#> <rvec_dbl<3>[1]>
#> [1] 0.09375,0.003906,0.003906
rmultinom_rvec(n = 1,
               size = 100,
               prob = c(0.1, 0.4, 0.2, 0.3),
               n_draw = 1000)
#> <rvec_dbl<1000>[4]>
#> [1] 10 (5, 16)  40 (31, 50) 20 (12, 28) 30 (21, 39)