On Wed, October 19, 2016 11:11 am, [Muniru Asiru] maas...@yahoo.com wrote: > > I need to factor large integers. One of then is > d:=208792137511016848023422421216659133913113038868420856362546192700228823547384086468768314408434778574357732094492450898877804848025959323284721735578041792204431293469827064868376517438126765900138542676486099702859181721290457656418761796076484288301990972494617227238953673093108532474354655441019362615154103484247530007425892848695540897;; > I tested d for being prime or not by using IsPrime(d); which returns false > which > confirms that d is composite.  > I tried PartialFactorization(d,6); which returns d. Also Factors(d); did > not return > a result in 15 minutes.  > How do I find the factors of d using GAP?
If the second-largest factor is 'relatively small', you can factor your number with GAP / FactInt if you just wait 'some longer'. How long it will take depends very much on the size of the factors and on good or bad luck. However if your number has two factors of roughly comparable size, you will need a dedicated program implementing the GNFS (generalized number field sieve) and either *A LOT* of patience or a supercomputer (note that your number is greater than a 1024-bit RSA modulus). Best regards, Stefan ----------------------------------------------------------------------------- http://www.gap-system.org/DevelopersPages/StefanKohl/ ----------------------------------------------------------------------------- _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum