[gecode-users] argmin

[Kish Shen]

Hi Christian,

Thanks again.

I have implemented the argmin/max constraints for gfd (the ECLiPSe 
Gecode interface), but I have several questions:

1) I am using Ints::Limits::max for the dummy 0th element of the 
IntVarArray. Is this the correct choice, or does using such a large 
number affect the comlexity of the computation?

2) The MPG says that if tiebreak is false, then the constraint is domain 
consistent. However, ICL_DOM is not mentioned in the reference 
documentation. Is this because the constraint is not domain consistent 
for tiebreak = true?

I have implemented the tiebreak = true and false as 2 constraints, and 
for the false case, the constraint can be posted as domain consistent. I 
hope this is correct?

Thanks and cheers,

Kish

On 25/06/2015 10:00, Christian Schulte wrote:
> Hi Kish,
>
> Thanks for the points. I'll address all of them a little later (end of
> semester rush here).
>
> Cheers
> Christian
>
> --
> Christian Schulte, www.gecode.org/~schulte
> Professor of Computer Science, KTH, cschulte at kth.se
> Expert Researcher, SICS, cschulte at sics.se
>
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
> Of Kish Shen
> Sent: Wednesday, June 24, 2015 10:50 PM
> To: users at gecode.org
> Subject: Re: [gecode-users] argmin
>
>
> Hi Christian,
>
> Thanks for the pointer. I assume as applied here, it is the index for the
> variable(s) in x that has the minimum value.
>
> I did not know (or at least remember) about argmin, and I don't know if it
> is common knowledge, so perhaps a little more explanation in the MPG might
> be helpful?
>
> I assume there is no offset that can be specified for this constraint, to
> offset the index, as is available for some of the other constraints?
> That is, in order to get this constraint so that the index start from 1, I
> need to add a dummy 0'th element to x?
>
> I think argmin is min_index in GCAT? This is not mentioned in the MPG, as is
> done for other constraints in the MPG, or am I missing some differences
> between argmin and min_index? (GCAT's minimum is also not mentioned for min)
>
> Cheers,
>
> Kish
>
> On 24/06/2015 10:45, Christian Schulte wrote:
>> Well it is just argmin:
>> 	https://en.wikipedia.org/wiki/Arg_max
>>
>> Christian
>>
>> --
>> Christian Schulte, www.gecode.org/~schulte Professor of Computer
>> Science, KTH, cschulte at kth.se Expert Researcher, SICS,
>> cschulte at sics.se
>>
>>
>> -----Original Message-----
>> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On
>> Behalf Of Kish Shen
>> Sent: Wednesday, June 24, 2015 9:41 AM
>> To: users at gecode.org
>> Subject: [gecode-users] argmin
>>
>> Hi,
>>
>> I am trying to understand the argmin/max constraints, but I don't
>> understand the description in the MPG (section 4.4.5 Arithemetic
>> constraints),L what does Chargmin(x) mean in:
>>
>> argmin(home, x, y)
>>
>> constrains y to argimin(x)?
>>
>>
>> Cheers,
>>
>> Kish
>>
>>
>> _______________________________________________
>> Gecode users mailing list
>> users at gecode.org
>> https://www.gecode.org/mailman/listinfo/gecode-users
>>
>
>
>
>
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