Dear Jason,

You can simulate a typeOfNextNext expression by using a secondary sequence variable that will be used to get the array index of the next interval of the sequence. Using this index, that you can determine the type of a successor/predecessor and follow the chained intervals in the sequence.

```
using CP;
int n = 10;
range r = 1..n;
range r0 = 0..n;
dvar interval itvs[i in r] size i;
// define a type for each interval (3 possible types)
int typeValue[r0] = [-1, 0, 0, 0, 1, 1, 1, 2, 2, 2, 2 ];
// sequence for types
dvar sequence seq
in all(i in r)itvs[i]
types all(i in r) typeValue[i];
// sequence for ordering
dvar sequence order in itvs types all(i in r) i;
dexpr int nextId[i in r0] = (i == 0 ? 0 : typeOfNext(order, itvs[i], 0));
dexpr int prevId[i in r0] = (i == 0 ? 0 : typeOfPrev(order, itvs[i], 0));
// used for printing the solution
dexpr int nextType[i in r] = typeOfNext(seq, itvs[i], -1);
dexpr int prevType[i in r] = typeOfPrev(seq, itvs[i], -1);
subject to {
// ensure the intervals do not overlap
noOverlap(seq);
// ensure the ordering of the two seqeuence is the same
sameSequence(seq, order);
// if an interval has a prev of same type
// then ensure that its next will have a different type
forall(i in r) {
(typeValue[i] != typeValue[nextId[i]])
|| (typeValue[i] != typeValue[nextId[nextId[i]]]);
}
}
execute {
writeln("itvs", itvs);
writeln("seq", seq);
writeln("order", order);
write(" index "); for(i = 1; i <= n; ++i) write("\t" + i); writeln();
write(" nextId "); for(i = 1; i <= n; ++i) write("\t" + nextId[i]); writeln();
write(" prevId "); for(i = 1; i <= n; ++i) write("\t" + prevId[i]); writeln();
write(" nextType "); for(i = 1; i <= n; ++i) write("\t" + nextType[i]); writeln();
write("typeValue "); for(i = 1; i <= n; ++i) write("\t" + typeValue[i]); writeln();
write(" prevType "); for(i = 1; i <= n; ++i) write("\t" + prevType[i]); writeln();
for(i = 1; i <= n; ++i)
if(prevType[i] == typeValue[i] && nextType[i] == typeValue[i])
print("ERROR: 3 consecutive intervals have the same type");
}
```

I hope this helps.

------------------------------

Renaud Dumeur

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Original Message:

Sent: Wed June 01, 2022 04:23 AM

From: Wu Jason

Subject: CPOptimizer sequence patterns

Hi,

I get some problem here, we can get the " next type of interval i " by function typeOfNext(seq,itvs[i])

Is there anyway to make the constraint like:

if( typeOfNext(seq,itvs[i]) != typeOf(itvs[i]) ) => typeOfNextNext(seq,itvs[i]) != typeOf(itvs[i])

By the way, thanks for the sharing!

----------------------------------------------

Jason Wu

----------------------------------------------

------------------------------

Wu Jason

Original Message:

Sent: Sat February 06, 2021 01:48 AM

From: ALEX FLEISCHER

Subject: CPOptimizer sequence patterns

Hi

could

https://github.com/AlexFleischerParis/opltipsandtricks/blob/master/positionofintervalinsequence.mod

from opl tips and tricks help ?

regards

------------------------------

[Alex] [Fleischer]

[EMEA CPLEX Optimization Technical Sales]

[IBM]

Original Message:

Sent: Fri February 05, 2021 11:39 AM

From: Luca Di Gaspero

Subject: CPOptimizer sequence patterns

Hello everybody,

I am looking for a way to impose some constraints that will avoid specific patterns of task types on sequences (something like the regular constraints in other CP systems). Actually, it would be enough to be able to express some constraint on just the two previous tasks in the sequence (something like the "typeOfPrevOfPrev"). Do you have any idea on how to model it?

Thanks in advance,

Luca

------------------------------

Luca Di Gaspero

------------------------------