The Skellam Distribution

Density and random generation for the Skellam distribution.

dskellam(x, mu1, mu2, log = FALSE)
rskellam(n, mu1, mu2)

Arguments

x

vector of quantiles.

n

number of observations. Same as runif.

mu1, mu2

See skellam

.

log

Logical; if TRUE, the logarithm is returned.

Value

dskellam gives the density, and rskellam generates random deviates.

Details

See skellam, the VGAM family function for estimating the parameters, for the formula of the probability density function and other details.

Warning

Numerical problems may occur for data if \(\mu_1\) and/or \(\mu_2\) are large. The normal approximation for this case has not been implemented yet.

See also

skellam, dpois.

Examples

if (FALSE)  mu1 <- 1; mu2 <- 2; x <- (-7):7
plot(x, dskellam(x, mu1, mu2), type = "h", las = 1, col = "blue",
     main = paste("Density of Skellam distribution with mu1 = ", mu1,
                  " and mu2 = ", mu2, sep = ""))  # \dontrun{}
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'y' in selecting a method for function 'plot': object 'mu1' not found