hd_add: Add two hyperdirichlet distributions
In hyperdirichlet: A Generalization of the Dirichlet Distribution

Description Usage Arguments Details Value Author(s) See Also Examples

Given two hyperdirichlet distributions, “add” them, in the sense of concatenating their information, assumed to be independent.

1	hd_add(e1, e2, assume_validated = FALSE)

`e1,e2`	Hyperdirichlet distributions of the same dimension
`assume_validated`	Boolean, with default `FALSE` meaning that the returned sum cannot be assumed to be proper; so the returned hyperdirichlet object is tested with `is.proper()` (which is time-consuming). Set to `TRUE` only when you know that the sum is proper

Think of this function as a computerized embodiment of Bayes's theorem with e1 representing the prior and e2 representing one or more informative trials.

The basic guts of the function is hyperdirichlet(powers(e1) + params(e2)). Note that this is equivalent to hyperdirichlet(params(e1) + powers(e2)).

The functional form is not really intended for the end user; use e1 + e2 instead (but observe that the sum will be validated using is.proper(), which may take a long time).

Returns a hyperdirichlet distribution

Robin K. S. Hankin

hyperdirichlet,is.proper,Arith

dirichlet(1:4) + gd(c(0.1 , 0.3 , 0.5), c(0.2 , 0.4 , 0.9))

uniform(4) + single_bernoulli_obs(4,1,2)

data(chess)
ch <- as.hyperdirichlet(chess)
stopifnot(all(params(ch+ch+ch) == params(ch*3)))