Hi there,

How can I use the sum function only from the second or later period (t=2) instead of all t? sum(t, periodutility(t))

Cheers

## Sum function from t=2

### Re: Sum function from t=2

Assuming that t is an orderd set (https://www.gams.com/latest/docs/UG_OrderedSets.html), you could use the ord operator:

I hope this helps!

Fred

Code: Select all

```
sum(t$(ord(t)>=2), periodutility(t))
```

Fred