dUnif: Discrete uniform prior distribution

In IPMbook: Functions and Data for the Book 'Integrated Population Models'

Discrete uniform prior distribution

Description

dUnif creates a vector or matrix to be used with the categorical distribution, dcat, in JAGS to generate a discrete uniform prior.

Usage

dUnif(lower, upper)

Arguments

lower, upper

Range of the discrete uniform prior. Either scalars, or vectors of the same length. Values are rounded to integers.

Value

If the arguments are scalar, a vector of length equal to upper, with the first lower - 1 elements filled with zeros and remainder holding a constant value such that the vector sums to 1.

Otherwise a matrix with each row constructed as above: the columns from lower to upper have a constant value, other columns hold zeros. See the examples.

Author(s)

Michael Schaub, Marc Kéry, Mike Meredith

References

Schaub, M., Kéry, M. (2022) Integrated Population Models, Academic Press, section 5.4.4.

Examples

# Both arguments scalar, vector output
(p <-  dUnif(lower = 4, upper = 8))
#  0.0 0.0 0.0 0.2 0.2 0.2 0.2 0.2
sum(p)
# Non-integer arguments are rounded
(p <- dUnif(lower = 3.8, upper = 8.2))  # same as above

# Vector arguments, matrix output
(p <- dUnif(lower = c(4, 2, 5), upper = c(8,11,6)))
# [1,]    0  0.0  0.0  0.2  0.2  0.2  0.2  0.2  0.0   0.0   0.0
# [2,]    0  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1   0.1   0.1
# [3,]    0  0.0  0.0  0.0  0.5  0.5  0.0  0.0  0.0   0.0   0.0
rowSums(p) # all 1

IPMbook documentation built on Aug. 22, 2023, 1:07 a.m.