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rnanarbitrary-precision

What if a number is divided by another too small number in R

I have tried that 1e-324 is basically zero in R. So, what should I do when I want to do some calculation like this:

1e-2000/1e-2000
#[1] NaN
#But the real value should be 1

So, any assistance is appreciated.

Solution

  • You need arbitrary-precision arithmetic. Take a look at gmp:

    library(gmp)
divide_by_zero <- function(n) {10^n / 10^n}
divide_by_nonzero <- function(n) {pow.bigz(10, n) / pow.bigz(10, n)}
divide_by_zero(-320:-330)
# [1]   1   1   1   1 NaN NaN NaN NaN NaN NaN NaN
divide_by_nonzero(-320:-330)
#Big Rational ('bigq') object of length 11:
# [1] 1 1 1 1 1 1 1 1 1 1 1