Processing one Bid at a time, the solution is simple: skip offers exceeding the Bid price.
If you have multiple Bids, select one (due to whatever) and mark it with a Token WME. This is developing into a very nice demo/exercise. The summary of requirements: (1) Bid: price, size (2) Offer: price, size, seqno (3) Collect Offer facts so that sum(size) >= Bid.size, price <= Bid.price (4) Offers must be used in increasing seqno Is this complete? I'm going to do implement this now. -W 2010/4/28 Andrés Corvetto <acorve...@gmail.com>: > The problem with this approach is that a Bid may not always match the head > of the list, because the price of the head Offer could be higher. > Given a Bid, I need to match it with the oldest Offer with equal o lower > price, and that Offer could be in any index of the list. > (Note that the previous approach did work, just not very efficiently) > - Andres > On Wed, Apr 28, 2010 at 6:13 AM, Wolfgang Laun <wolfgang.l...@gmail.com> > wrote: >> >> Here is another way of matching Offers first-in first. It is based on >> a linked list connecting new Offers the way they arrive. You'll need >> another WME OfferList containing references to the head of the list >> and to the last element. An unlinked new Offer is added at the end. >> Matching is now done by looking at the "head" field of the OfferList >> WME, and a matched Offer is removed from the list. You'll probably >> need another field in an Offer to indicate the status (new, unmatched, >> matched) so that you don't get cycles in your loop firings. >> >> -W >> >> On Wed, Apr 28, 2010 at 3:43 AM, Andres Corvetto <acorve...@gmail.com> >> wrote: >> > >> > Thank you for your answers. >> > >> > I tried this approach (which yields much more elegant rules), but i'm >> > afraid >> > it does not perform very well. >> > If I insert 10000 Offers and then 1 bid, it takes too much time to >> > execute. >> > If understand correctly it's because of the "not >> > Offer(creationTimestamp < >> > $ct)" clause in the LHS, which forces a comparison of every matching >> > Offer >> > against every other Offer. >> > >> > The motivation for my original post was to find a way of achieving the >> > results of an accumulator without having to sort all the matching Offers >> > by >> > creationTimestamp. >> > Going back to that first approach (using an accumulator), I found that >> > Drools feeds the accumulator with the matching Offers in reverse order >> > (ie, >> > newest first, LIFO). >> > Is this a natural consequence of the way facts are stored in the working >> > memory or is there a way of changing this behaviour (so that oldest are >> > feeded first, FIFO)? >> > >> > Thanks again >> > >> > - Andres >> > >> > -- >> > View this message in context: >> > http://drools-java-rules-engine.46999.n3.nabble.com/Rule-using-accumulate-tp757311p761181.html >> > Sent from the Drools - User mailing list archive at Nabble.com. >> > _______________________________________________ >> > rules-users mailing list >> > rules-users@lists.jboss.org >> > https://lists.jboss.org/mailman/listinfo/rules-users >> > >> >> _______________________________________________ >> rules-users mailing list >> rules-users@lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users > > > _______________________________________________ > rules-users mailing list > rules-users@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > _______________________________________________ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
