ILOG OPL Development Studio Language Reference Manual

♦prev(p, a, b) states that if both intervals a and b are present then a will be just before b inthe sequence p, that is, it will appear before b and no other interval will be sequencedbetween a and b in the sequence.The formal semantics of these basic constraints is shown in the following table.The no overlap constraintThe no overlap constraint on an interval sequence variable p states that the sequence definesa chain of non-overlapping intervals, any interval in the chain being constrained to end beforethe start of the next interval in the chain. This constraint is typically useful for modellingdisjunctive resources.More formally, the condition for a permutation valueconstraints is defined as:for sequence p to satisfy the noOverlapIf a transition distance matrix M is specified, it defines the minimal distance that must separatetwo consecutive intervals in the sequence.More formally, if T(p,a) denotes the integer type of interval a in the sequence variable p:A sequence variable together with a no-overlap constraint using it are illustrated in this figure:I L O G O P L D E V E L O P M E N T S T U D I O L A N G U A G ER E F E R E N C E M A N U A L159