Originally posted by: Mahmoud Fayek

In the "Multi-mode resource-constrained project scheduling" Provided Example,
How to constraint the modes choosing process like; the sum of some value in the mode definition for all chosen modes must equal  a value.

To access this example, go to: examples/opl/sched_rcpspmm.

Originally posted by: GGR

Hi Mahmoud

To model the modes in sched_rcpspmm., an alternative constraint tells that a task[t] interval variable is an alternative among itsmodes[m]  interval variables.

 alternative(task[t], all(m in Modes: m.taskId==t.id) mode[m]);

An optional internal variable it allow to tell a constraint presenceOf(it) that is true if and only if the interval variable is present.

Then you can use this constraint as a Integer [0,1] expression to post constraint. For an unrealistic example, the pondered by task, sum of the mode selection must be less than a constant c

sum (t in tasks) t.taskId*presenceOf(mode(<t.task.id, 0>)) <= c;

You can have a look on

https://www.ibm.com/support/knowledgecenter/en/SSSA5P_12.8.0/ilog.odms.cpo.help/refcppcpoptimizer/html/interval_variables.html

https://www.ibm.com/support/knowledgecenter/en/SSSA5P_12.8.0/ilog.odms.ide.help/OPL_Studio/opllang_quickref/topics/tlr_oplsch_presenceOf.html

https://www.ibm.com/support/knowledgecenter/en/SSSA5P_12.8.0/ilog.odms.ide.help/OPL_Studio/opllangref/topics/opl_langref_scheduling_logical.html

Hope that helps

Originally posted by: Mahmoud Fayek

Thank you very much.