[R] big numbers

[Robin Hankin]

Hi

Can I get R to handle really big numbers?    I am not interested
in more than (say) 10 sig figs, but I would like to deal with numbers
up to, say, 10^10000.

If

a <- 10^10000
b <- pi* a

I would like  "a+b" to return 3.1415926e10000.


Toy example, illustrating why I can't deal with log(a) and log(b),   
follows.



f <- function(a,n=100){
   out <- rep(0,n)
   out[1] <- a
   for(i in 2:n){
     out[i] <- sum(exp(out[1:i])) + rexp(1)
   }
   return(log(out))
}


then f(1,10)  has infinities in it, even though the values should be  
moderate size.

What are my options here?

--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743