Dealing with very small numbers in R

Question

I need to calculate a list of very small numbers such as

(0.1)^1000, 0.2^(1200),

and then normalize them so they will sum up to one i.e.

a1 = 0.1^

Answer 1

The Brobdingnag package deals with very large or small numbers, essentially wrapping Joris's answer into a convenient form.

a1 <- as.brob(0.1)^1000
a2 <- as.brob(0.2)^1200
a1_dash <- a1 / (a1 + a2)
a2_dash <- a2 / (a1 + a2)
as.numeric(a1_dash)
as.numeric(a2_dash)