[eclipse-clp-users] Column generation with colgen

From: Sergii Dymchenko <kit1980_at_...6...>
Date: Mon, 8 Jul 2013 16:50:53 -0700

I can't find any simple examples how to use colgen library.

There is an example in "ECLiPSE: A Tutorial introduction", but it's more
than 2 pages of code and not easy to understand.

I've found a very short and easy to understand cutting stock example in
slides from Mark Wallace "Hybrid algorithms, local search, and Eclipse"
(First International Summer School on Constraint Programming, 2005,

:- lib(ic), lib(colgen).

solve(Cost) :-
    Vars = [Threes,Fives,Nines], Vars #:: 0..10,
    3*Threes+5*Fives+9*Nines #= Used,  Used #=< 17,
    Waste #= 17-Used,
    colgen: (sum(Threes) >= 25),
    colgen: (sum(Fives) >= 20),
    colgen: (sum(Nines) >= 15),
    minimize(my_solve(C,Vars), sum(Waste), Cost).

my_solve(C,Vars) :-
    colgen: sol(C,Vars).

The problem is that ECLiPSe and colgen library have changed so much from
2005, and I have no idea how to modify the example to work with recent
ECLiPSe version (probably, changing 'sum' to identified_constraint with
implicit_sum is needed, plus other things).

Maybe someone with more colgen knowledge can help me to modify the example
to work with recent ECLiPSE?

Received on Mon Jul 08 2013 - 23:51:02 CEST

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