A Browsing Odyssey

By Stephen Pickett, author of BRidgeBRowser

(an illustration of how to use BRBR)


23-May-2001: Player indexing now works instantly!

With all the talk about Louts and Lotts of trumps, as the author of this tool, I felt it was important to give an example of how you can use it for practical everyday purposes, such as improving one's own game, and reviewing the actions of opponents.

I decided to start by looking at all slams that I had bid or defended in okbridge over the course of my membership (admittedly the data is not complete, but at least from the data we have).

I retrieved all the hands I had ever played that were in the database. I could just as easily search for only slam hands, but generally it makes sense to the whole thing, since it costs no more time, I can always look at some other aspect of my own hands later, since I am going to save it. The beginning of that looked like this:

About an hour later (NOTE: should be instant with the new release, 22/5/2001), I had a display where the bottom right hand corner looked like this:

You need to understand at this point WHY it took so long to do this search. I had searched some 250,000 boards, and some 15,000,000 hands. (sure, on 4,000 of those boards, I was able to skip to the next one, but overall that is fairly insignificant, because in the majority of boards that I didn’t play, every play was searched to see if I played it.).

23/5/2001 NOT ANY MORE!!!! Play files are bigger but so are people's disks!

(See digression below about indexing)

Now we save that lot into a file (following the nice instructions done by Carl in the Help file - press F1 in BRBR and search for Hudecek in the keywords list).

Before I do anything else, I'll do a partner scan: the top ten entries for overall boards played correspond to the top ten in the chart on the left. That takes about 30 seconds. Works faster if you turn off the chart and reenable at the end, too. If you double-click one of the players you go directly to their stats and played hands.

If you ever wonder why success isn't leading to ratings improvement, you can also press that button marked "Show opponents" and scan the calibre of all your opponents. Works like a charm, if I do say it myself.

Back to the main screen. I can now throw away everything except slams (the file is saved so a search again is easy), leaving only those contracts of interest.

Here are the results:

Not too bad. This is playing AND defending slams before anyone gets carried away J

To narrow my search further, I will stick to IMPs. So we adjust the parameters accordingly. They will look like this:

Now I am going to start looking seriously at contracts.

Finally I am going to select "Defend only" and arrange the results by clicking on the "points" column header to put the biggest losses at the top of the screen. Here's what I get:

Hmm.... grand slams are always hard to bid, lets look at that 7S - double click it. And press that "view duplicate" button, I want to see how everyone else did.

As I suspected, the lost imps are all in the bidding. Out of 74 pairs, most played in 6S, all made 13 tricks, and at only thirteen tables was the grand slam bid.

I could press the BridgeVu button but for now I am going to write some commentary. Remembering to save what I write, now I press the BridgeVu button at the point where declarer leads a small heart from hand.

A few clicks later, I have this:

Just another lucky slam.

What about this one:

This looks a lot more like we got fixed. Both of the players opposing are now gone from okb or changed their names. That bidding is looking pretty insupportable.

I'm going to pull khh01's chart. He made a lot of points that week, for an overall score of about +150 imps. Double click on his name.

300 "towards-ratings" points in a single week is a lot, trust me. Our friend with three accounts only ever managed about 700 of those in his very worst spree.

The blue highlighted line is the week which the hand of interest came up in. Double click it for a scan of those boards. Arrange by partner by clicking on the appropriate column.

Interesting! A lot of the hands were partnering khh03, who seems to have a rating of about 64 in IMPS.

Oh well, enough, I think that's good enough to get the general idea.

HAPPY BROWSING (to bend slightly the catchphrase of at least one other Bridge site)!

Go back to BRidgeBRowser central

Here's the digression that the reviewers thought got in the way of the narrative:

Digression: what about an index, you say. Minor problem, the index would probably double or even triple the size of the file.

(23/5/2001) I was wrong: the index grew the file by about 30%).

However there are some ways around it that enable us to zoom in quite quickly despite the lack of performance in a linear search. I'd love to know how to index 20,000,000+ hands easily. We tried adding fields that index one integer and it appeared to increase the file by over 200MB. Maybe this issue can be revisited. But indexing the file by all four players seems like a problem at the moment. The other problem is some players play almost no boards, others play tens of thousands, and so the index is not exactly uniform in texture, and thuse not very susceptible to some optimization techniques such as hashing (please someone correct this misconception if you can!).