[julia-users] Factorization of big integers is taking too long

[Hans W Borchers]

I got interested in factorizing some larger integers such as N = 3^100 + 2 .
In all tries, factor(N) did not return and had to be interrupted:

    julia> N = big(3)^100 + 2
    julia> factor(N)
    ^CERROR: interrupt
     in finalizer at ./base.jl:126
     in + at gmp.jl:243
     in factor at primes.jl:111

It is calling GMP, but the GMP software cannot be the reason as this works 
with the GMP package in R and returns the factorization within seconds:

    R> library(gmp)
    R> N <- bigz(3)^100
    R> factorize(N)
    Big Integer ('bigz') object of length 3:
    [1] 31721   246451584544723     65924521656039679831393482841
    R> system.time(factorize(N))
     user  system elapsed 
    3.738   0.000   3.730

Is this a bug? Did I do something wrong?
The first factor, 31721, is not even large. Mathematical software such as 
GAP or PARI/GP will factorize this in much less than a second.

PS: Versioninfo
    Julia Version 0.3.6; System: Linux (x86_64-linux-gnu)
    CPU: Intel(R) Core(TM) i3-3217U CPU @ 1.80GHz; WORD_SIZE: 64
    BLAS: libblas.so.3; LAPACK: liblapack.so.3
    LIBM: libopenlibm; LLVM: libLLVM-3.3