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, [email protected]
Expert Researcher, SICS, [email protected]

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Kish Shen
Sent: Wednesday, June 24, 2015 10:50 PM
To: [email protected]
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, [email protected] Expert Researcher, SICS,
[email protected]


-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Kish Shen
Sent: Wednesday, June 24, 2015 9:41 AM
To: [email protected]
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


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