Re: [eclipse-clp-users] help with gcc_matrix

Hi Geoff,

Thanks for your posts about gcc_matrix -- this is one of the several new 
global constraints that was recently contributed to ECLiPSe, so they are 
still in a prototype stage, so we particularly welcome any feedback on 
their use.

Moon, Geoff wrote:

> Force a 3 into row 2 - incorrect?
> Rows =[[gcc(0,1,1),gcc(0,1,2),gcc(0,1,3),gcc(0,1,4)],
>        [gcc(0,1,1),gcc(0,1,2),gcc(1,1,3),gcc(0,1,4)]]
> Cols =[[gcc(0,1,1),gcc(0,1,2),gcc(0,1,3),gcc(0,1,4)],
>        [gcc(0,1,1),gcc(0,1,2),gcc(0,1,3),gcc(0,1,4)]]
> Matrix =[]([](1,2),[](2,1))
>

Yes, this (and the other instances) do look incorrect to me, too.


> 1. Forcing values to NOT appear (ie gcc(0,0,X)) is always correct.

The non-matrix version of this constraint (gcc) does not require the 
values that have 0 cardinality (as in your first post), so I think it 
should not be required here too. I think this should be quite easy to fix.

> 2. The low limit can be larger than the high limit without causing an
> error. 

This looks like another problem, as the constraint seems to succeed and 
give a "solution" in such cases. I am not sure if it should give an 
error in such cases, perhaps it should just fail (like when you give a 
domain with the lower bound larger than the upper bound)

> 3. I am using build #121 for windows.
>
The constraint is written entirely in ECLiPSe, and the problems occur on 
other platforms as well.

We will look into the problems and try to fix them. Thanks for letting 
us know! I guess for the moment, you may want to use individual gcc for 
your problem, rather than gcc_matrix

Thanks and cheers,

Kish





You reported instances of incorrectly behaviours does look like bugs to 
me, and also the lower limit being
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