Originally posted by: SystemAdmin

[Optimizatron said:]

I need some genious help... working on a model which schedules jobs with the goal of minimizing resource usage, while meeting job time windows.  My formulation is below... seems like it should work, but I have a syntax error telling me that I can't use the dvar for job starting time to define a summation range (in the first constraint).  Any workarounds or alternative formulations for this?

int numJobs = ...;
range Jobs = 1..numJobs;
int numPeriods = ...;
range Periods = 1..numPeriods;
int earliestStart[Jobs] = ...;
int latestStart[Jobs] = ...;
int serviceTime[Jobs] = ...;

dvar boolean startJob[Jobs][Periods];
dvar boolean busyResource[Jobs][Periods];
dexpr int startTime[j in Jobs][t in Periods] = t*startJob[j][t];

minimize maxl (sum (t in Periods, j in Jobs)busyResource[j][t]);

subject to {

forall (j in Jobs)
sum (t in Periods:startTime[j][t]<=t<=t+serviceTime[j]+1) busyResource[j][t]== serviceTime[j];<br />
forall (j in Jobs)
sum (t in Periods:earliestStart[j]<=t<=latestStart[j])startJob[j][t]==1;<br />
};

#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[alain.chabrier said:]

Hi,

just a question/suggestion : did you look at the CPO Scheduling modeling and engine from OPL ?
You should look at examples in examples/opl which start with sched_.

OPL offers specific modeling construct for these kinds of problems, and CPO offers a specific engine to solve efficiently these problems.

Alain
#DecisionOptimization
#OPLusingCPLEXOptimizer