[gecode-users] Cumulative constraint propagation
Mikael Zayenz Lagerkvist
zayenz at gmail.com
Tue Mar 6 15:32:08 CET 2007
On 3/6/07, Jérémie Vautard <jeremie.vautard at laposte.net> wrote:
> I asked a few month ago (October 4th) what propagation the cumulative
> constraint did (*Mikael Zayenz Lagerkvist answered me that it did not
> very much). Does it do more now ?
It does not do anything more. The constraint implemented, called
cumulatives, is a very general constraint. To read more about the
specific prunings done, see "A New Multi-resource cumulatives
Constraint with Negative Heights" by Beldiceanu and Carlsson
> Could someone indicate me a paper describing the state of the art in
> this domain ?
Bounds-consistent pruning for cumulative is NP-complete, so we must
look for weaker algorithms. Some common algorithms used are edge
finding, not-first/not-last, and energetic reasoning.
The most complete reference for scheduling constraints is probably
"Constraint-Based Scheduling" by Baptiste, Le Pape, and Nuijten
For some updates on edge-finding for cumulative constraints, see "Edge
Finding for Cumulative Scheduling" Mercier and Van Hentenryck
Hope this helps,
Mikael Zayenz Lagerkvist, http://www.ict.kth.se/~zayenz/
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