[rules-users] Planner: What is a good example/algo to chain entities?

Hi, I need to keep some Planning entities (Tasks) together and I am looking for some insights/ideas/examples in how to tackle this. Tasks are grouped by a groupId (Groups are problem facts). The Tasks do not have to be grouped like a pillar but more like an accordion. One of the planning variables is "Period", a Period typically is 3 weeks and we have 12 Periods to plan the tasks into. The requirement is that all tasks within  a group need to be kept together in such a way that: - the spread (nr of periods) of the tasks is minimal - the spread is never more than the sum of the duration of the separate tasks in the group. So given a group of 3 tasks: 1)This is good: Period 12345789ABC T1:      xxx T2:         xx T3:           x 2)This is better: Period 12345789ABC T1:      xxx T2:       xx T3:         x 3)This is (one of) the best: Period 12345789ABC T1:      xxx T2:       xx T3:        x 4)This is bad: Period 12345789ABC T1:      xxx T2:       xx T3:          x Of course 3 is favorite, but maybe not possible due to other planning variables (-> availability of people to execute the tasks). I need to plan a few hundred of such groups of tasks which all share the same Period space and list of available people. (A person can only do one task per period) I have got the DRL rule that keeps the tasks together (rule counts the gaps) , but giving penalty for making gaps (by shifting a single task) makes it hard to find a good solution. What would be the best approach to solve this problem? - A combination of custom mover and swapper which moves/swaps groups instead of single tasks? - The above in combination with a group shuffle factory (swapping tasks in a single group)? Other ideas? Thanks a lot! ----------------- http://www.codessentials.com - Your essential software, for free! Follow us at http://twitter.com/#!/Codessentials