[gecode-users] Arbitrary big numbers?

[Kish Shen]

Hi Slav,

I guess I should first state that I have been working as a developer for
ECLiPSe since 1998, and what I say here is personal and from an ECLiPSe
perspective.

>How *just* an interface can be able to have numbers bigger than underlying
library?

I am not sure what you mean by 'just an interface', but as the slides in
your link describe, ECLiPSe is a programming language. It has an interface
to Gecode, which will allow you to use Gecode in a program written in
ECLiPSe, with essentially the same syntax as the native finite domain
solvers of ECLiPSe, such as the interval solver (ic) described in the
slides you linked to.

ECLiPSe supports big integers if it was built with GMP. However, you can
only use these integers when you are performing your arithmetic operations
in ECLiPSe. You cannot use such integers when you are using an external
solver such as Gecode. In fact, you cannot use big integers even with the
native finite domain solvers of ECLiPSe
(the intervals in lib(ic) are represented using (C floating point type)
double, and the integer range is the range of integers that can be
precisely represented with a double).
.
On a more general point, one of the reasons why ECLiPSe does not support
big integers even for native finite domain solvers is that in practice,
modelling finite domain problems with very large ranges is not likely to be
an effective way of solving such problems. This is our experience with
ECLiPSe, I guess Christian or other people on this mailing list may have a
different view.

Cheers,

Kish Shen


On Wed, Aug 2, 2017 at 8:01 PM, Christian Schulte <cschulte at kth.se> wrote:

> Gecode is but one of the solvers to which Eclipse has an interface.
> Christian
>
>
>
> --
>
> Christian Schulte, www.gecode.org/~schulte
>
> Professor of Computer Science, KTH, cschulte at kth.se
>
> Expert Researcher, SICS, cschulte at sics.se
>
>
>
> *From:* Slav [mailto:slavmfm at gmail.com]
> *Sent:* Wednesday, August 2, 2017 19:38
> *To:* cschulte at kth.se
> *Cc:* users at gecode.org
> *Subject:* Re: [gecode-users] Arbitrary big numbers?
>
>
>
> Thank for your answer :)
> If so, I cannot understand that "ECLiPSe Integers can be as large as fits
> into memory, e.g.: 123 0 -27 393423874981724"
> <http://gki.informatik.uni-freiburg.de/teaching/ws1415/csp/csp11.pdf>,
> but Wikipedia says <https://en.wikipedia.org/wiki/ECLiPSe> that:
>
> ECLiPSe interfaces to external solvers, in particular the Gecode solver
> library
>
> How *just* an interface can be able to have numbers bigger than
> underlying library?
>
>
>
> 2017-08-02 0:24 GMT+04:00 Christian Schulte <cschulte at kth.se>:
>
> Hi, unfortunately there is no support for this. We know that this is high
> on the wish list of many but… I think somebody has tried, if I recall
> correctly, though. Guido, do you have any details.
>
>
>
> Cheers
>
> Christian
>
>
>
> --
>
> Christian Schulte, www.gecode.org/~schulte
>
> Professor of Computer Science, KTH, cschulte at kth.se
>
> Expert Researcher, SICS, cschulte at sics.se
>
>
>
> *From:* users-bounces at gecode.org [mailto:users-bounces at gecode.org] *On
> Behalf Of *Slav
> *Sent:* Tuesday, August 1, 2017 20:23
> *To:* users at gecode.org
> *Subject:* [gecode-users] Arbitrary big numbers?
>
>
>
> Hello. I am modeling algorithm to hardware mapping with *Gecode*.
> Standard *Int::Limits::max* is too small because I want to target systems
> with more than 2^31 memory.
>
> Is there a way to get use of arbitrary-precision arithmetic with Gecode or
> at least 64-bits integers?
>
> I know that Gecode can be built with *MPIR* or *GMP* support, but seems
> those are just for trigonometric operations?
>
> Thanks in advance :)
>
>
>
> _______________________________________________
> Gecode users mailing list
> users at gecode.org
> https://www.gecode.org/mailman/listinfo/gecode-users
>
>
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