[R] Problems trying to generate a prime factor vector

Franklin Bretschneider bretschr at xs4all.nl
Thu Dec 3 14:29:46 CET 2015

Hi Kevin Wright,

> I am very new to 'R' and am trying to write an R function which returns the
> prime factors of a given number(n)
> Unfortunately, the function only works for very small numbers, if for
> example I pass 18 to the function
> a mysteriously long vector is returned. I have not been able to find where
> or why this is happening.
> I know I've done something wrong. I've tried using debugging statements.
> Sometimes the
> currentPrime variable seems to become some sort of array?!
> can you help?
> library(gmp)

But why writing one? Such a function is already in gmp: factorize(n), and
it works with fairly large numbers:

Big Integer ('bigz') object of length 13:
 [1] 2   2   2   2   5   7   11  73  101 109 109 137 167



Franklin Bretschneider
Dept of Biology
Utrecht University
bretschr at xs4all.nl

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