[Coin-standards] Technical Item! CLP

[Leonardo B. Lopes]

Wow! This sounds like real progress. Cols and Rows are objects in SNOML,
and something like your example could be done today using it. It might
actually be quite simple to merge the CLP expressions and the current
version of SNOML, assuming the CPML (?) has a closing tag for expressions,
like <math> in MathML. It also shouldn't be hard to keep the
column-as-object requirement as we move forward in other directions.

Leo.

On Fri, 19 Apr 2002, Irv Lustig wrote:

> At 12:17 PM 4/12/02 -0500, Leonardo B. Lopes wrote:
> >Could you invite some ILOG CP person into the list?
> 
> I spoke with Laurent Perron of the ILOG R&D person.  Laurent is a
> key contributor to ILOG Concert Technology, which is our effort to
> come up with representations (in C++ and Java) for CP and MP.
> Laurent is busy on another project right now, but intends to
> contribute an XML proposal for CP to the list in the near future.
> 
> One of the points that Laurent made is that an LP matrix
> of constraints needs to be considered a potential "constraint"
> in the CP representation.  This means that one needs to treat
> variables as objects, so that when a set of linear constraints
> are given, you know which variables are involved.
> 
> For example, one could imagine a problem of the following form
> (using a bastardized OPL):
> 
> var int x[1..10] in 0..100;
> var int y[1..10] in 0..100;
> 
> /* Constraints */
> 
> forall (i in 1..5) {
>     sum (j in 1..10) ax[i,j]*x[j] +
>     sum (j in 1..10) ay[i,j]*y[j] = b[i];
> };
> alldifferent(x);
> 
> The first set of constraints are linear constraints and correspond
> to a matrix.  The next constraint is alldifferent(), but only on
> a subset of the variables.
> 
> The point here is that a set of linear constraints is at the
> same "object level" as any of the CP constraints.
> 
>          -Irv
> 
> 
> 
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========================================================================
Leonardo B. Lopes                                       leo at iems.nwu.edu 
Ph.D. Student                                              (847)491-8470
IEMS - Northwestern University              http://www.iems.nwu.edu/~leo