[Cado-nfs-discuss] Using GPU in Sieving Step

Shi Bai shih.bai at gmail.com
Wed Aug 15 15:33:14 CEST 2012

Hi Hamid, Zach,

On Sat, Aug 11, 2012 at 11:06 PM, Zachary Harris
<zacharyharris at hotmail.com> wrote:
> Hamid,
>   Someone with greater expertise can correct me if I'm wrong, but I believe
> that, as a complete factorization algorithm itself, ECM is independent of
> NFS and therefore your answer is "No", it is in no way useful for the
> sieving part of NFS (i.e. ECM is not a sieve).
>   As a rough heuristic, if I have a large number to factor, I'll hit it with
> ECM first to quickly pull out any small (~25 digit) factors, and then if the
> remaining factor is 60 digits or more I'll let NFS handle that.

It's more likely that Hamid mean the ECM for the cofactorization step?

> On 08/11/2012 01:40 AM, hamid reza arkian wrote:
> Hi,
> I have sent some questions 4 days ago, but I have not received any answer
> yet.
> Can anyone help me, please?

I know that some members of the CADO-NFS team are on holidays these
days so they may not see this.

> Thanks,
> Hamid
> On Tue, Aug 7, 2012 at 11:36 AM, hamid reza arkian <hamid.arkian at gmail.com>
> wrote:
>> Hi,
>> I tried GMP-ECM project (the branch that is currently under active
>> development for GPU devices) on a GPU cluster and got good results.
>> I want to replace ecm part of sieving step in CADO-NFS with GMP-ECM(that
>> support GPU), but I have the following questions:
>> - Basically, it's a good idea or not?
I personally think it's a good idea (though I admit I haven't wrote
codes for the sieving part.) But there could be some issues, such as
the stage 2 memory requirement. PS: I've CC-ed this email to Alex
Kruppa, who can answer this much better.

Kind regards,

>> - Is the GMP-ECM faster than ecm part of CADO-NFS? and if so, why the
>> developers don't do this replacement,yet?

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