Originally posted by: RuiFig

hi, 

I would like to know  how to indicate that an activity can only start after a certain time.

i try to use this 

forall( j in products, o in machines){

startOf(itvs[j][o])>start[o];

}

but it doesn t work, 

can anyone help me ? 

Can you please elaborate on what you mean by "it does not work"?

Originally posted by: RuiFig

the result is not what i expect to be. 

but i think i have already found why 

i have a produtc that folows the this sequence of machines[ 1 4 18 5......] but the in the variable itvs[j][o] if i want to use machine 18, o needs to be equal to 3.

there is any way i can convert the o in itvs directly to the machine? 

This can be done using an additional array that provides reverse lookup:

range M = 1..4;
int machines[M] = [ 1, 4, 18, 5 ];
int idx[{ machines[m] | m in M}] = [ machines[m] : m | m in M ];
execute {
  for (var m in M) {
    var mach = machines[m];
    writeln(mach, ": ", idx[mach]);
  }
}