[rules-users] Using Drools Fusion to compute overlaps of many intervals

Hi Drools guys. I just asked the following question on StackOverlow<http://stackoverflow.com/questions/18219841/using-drools-... . Could you please help : I am already using Drools to do some *preprocessing of an allocation problem * (resources vs operations). The operations are already time *intervals* but I did not need to leverage the Drools Fusion features yet. There is a new requirement for having some *attributes of my resources changing over time*. I am willing to model this (the change of values over time) as *"events" in Drools* and take advantage of Drools Fusion, in *Cloud* mode. Hence I will have to match those "dynamic" attributes events against my operations (again declared as events in Drools fusion). This will require Drools to *compute a great amount of intervals overlaps*. I have several questions : - I have found the *overlap* operator to be kind of counter-intuitive, and to not actually process*overlap* as we usually describe it. I would expect [a;b] and [c;d] to overlap if *(b > c) and (a < c)*. Is there a time operator for that ? Or should I use a composition of several time operators ? - Does Drools Fusion uses any kind of internal optimization for this kind of problem ? Naively matching N intervals against M intervals would require *0(N x M)* operations. I have found a way to go down to *(M x log(M) + N x log(N))*, by sorting the intervals beforehand : Should I prepare the pair of overlaps for Drools in advance ? - Related to the previous question : Is there any benefit in this case (in term of performances), of using *Drools Fusion* instead of *regular Drools* together with conditions over timestamps and duration ? Thanks for your advice Brgds, -- Raphael