leader Board Rankings

[desert dawg]

I have noticed for a while on some leader boards the rankings a bit

Take a look at Box Elder County Utah
Virtual Leader Board
there are 10 virtual caches available in the county worth a total of 39 points.
24 cachers have earned the 39 points available.. out of the 24 :
12 cachers are ranked #1.
12 cachers are ranked #13.
I have noticed this on a few other leader boards like the Box Elder County Virtual leader board as well.
a couple in Davis county Utah only the few top names are ranked #1 the rest with same total points score jump to ranked #5 or ///.

was wondering if you can only have a certain percentage on any board ranked as #1 ? and on those boards there is No #2, #3, #4 ..............
thanks
dawg

[Corfman Clan]

This is most likely caused by the limited precision on how floating point numbers (numbers with fractional parts) are stored on computers. The score for each cache found by a cacher is summed up and that is what is used to rank cachers in the leaderboards. I presume order of summation may make a slight difference in the result due to this "floating point error" and that is why cachers may be ranked differently even though they've found the exact same caches.

I noticed this before with the Owner/Finder rankings and made a correction that seems to work well enough. I'll incorporate that change into the leaderboards as well. Basically, we sum all the points using the SQL Server function SUM(). I'll just limit the precision of the result by rounding it to 5 or 6 decimal places. This basically hacks off the part of the result where errors creep in. This is easily done by wrapping the SUM with the SQL Server function ROUND() as follows:

Code: Select all

ROUND(SUM(points),6)

So extending the Elder Box County Virtual Leaderboard example, the first 12 cachers points may sum to
39.123456789012
while the next may sum to
39.123456789011
When we apply ROUND to the sums we now get
39.123456
for all 24 cachers and now they will all be ranked the same.

[desert dawg]

well that pretty much sums () the issue up, its a wrap, (around) .... wee bit over my head, thanks for the explanation.

[rocketsciguy]

I have noticed for a while on some leader boards the rankings a bit

Take a look at Box Elder County Utah
Virtual Leader Board
there are 10 virtual caches available in the county worth a total of 39 points.
24 cachers have earned the 39 points available.. out of the 24 :
12 cachers are ranked #1.
12 cachers are ranked #13.
I have noticed this on a few other leader boards like the Box Elder County Virtual leader board as well.
a couple in Davis county Utah only the few top names are ranked #1 the rest with same total points score jump to ranked #5 or ///.

Dawg, this question wouldn't at all have been prompted by the fact that you are exactly 2 caches away (1 Virtual, 1 Multi) from completely dominating the Leaderboards in Box Elder with #1s in every category? Well, that is, assuming this round off error problem is fixed so you'd end up in a 23-way tie for #1 in Virtuals and not a 16-way tie for #8 with a score a hair's breadth less than the #1s and no way to move up? I may have to put out a Whereigo or two just to keep you on your toes!

[desert dawg]

I have noticed this on a few other leader boards like the Box Elder County Virtual leader board as well.
a couple in Davis county Utah only the few top names are ranked #1 the rest with same total points score jump to ranked #5 or ///.

Dawg, this question wouldn't at all have been prompted by the fact that you are exactly 2 caches away (1 Virtual, 1 Multi) from completely dominating the Leaderboards in Box Elder with #1s in every category? Well, that is, assuming this round off error problem is fixed so you'd end up in a 23-way tie for #1 in Virtuals and not a 16-way tie for #8 with a score a hair's breadth less than the #1s and no way to move up? I may have to put out a Whereigo or two just to keep you on your toes!

What can I say.. Box Elder County has been my playground since the early 1960's. I know every two track , rock formation , gully and cave out there. Guess I better move up that way... A Whereigo sounds fun.. I do not have one as yet. I have been trying to get top Box Elder Co resident cacher GJG6 active again looks like he has retired form caching, not one find in 2013 ? I'm OK hangin in at #46 in the B. E. virtual category for now.. Time to work on Tooele and Juab a little..

[Corfman Clan]

I believe I have the fix for this now, it will be included in the next site update. I tried rounding to six decimal places and the problem still persisted so I tried with 5 and that seems to work, at least with my test data.

[desert dawg]

I believe I have the fix for this now, it will be included in the next site update. I tried rounding to six decimal places and the problem still persisted so I tried with 5 and that seems to work, at least with my test data.

Thanks CC, the update did do what intended.. I still have a Q about the
Virtual cache leader board ; Weber County Utah..
only one cacher ranked #1 but a bunch of cachers ranked #2 (all with the same point total ? )

If I'm getting to be a pain in the arse.. with these minor issues, sorry... let me know.. ha
dawg

[Corfman Clan]

I believe I have the fix for this now, it will be included in the next site update. I tried rounding to six decimal places and the problem still persisted so I tried with 5 and that seems to work, at least with my test data.

Thanks CC, the update did do what intended.. I still have a Q about the
Virtual cache leader board ; Weber County Utah..
only one cacher ranked #1 but a bunch of cachers ranked #2 (all with the same point total ? )

I think since we're rounding to 5 digits for the Finder and Hider boards, then summing the results for the combined boards, that the combined boards should be rounded to 4 digits, not 5 and that will take care of this. I'll give that a shot.

If I'm getting to be a pain in the arse.. with these minor issues, sorry... let me know.. ha
dawg

Not at all, it's a good thing to correct all this. Thank you.

[Corfman Clan]

I believe I have the fix for this now, it will be included in the next site update. I tried rounding to six decimal places and the problem still persisted so I tried with 5 and that seems to work, at least with my test data.

Thanks CC, the update did do what intended.. I still have a Q about the
Virtual cache leader board ; Weber County Utah..
only one cacher ranked #1 but a bunch of cachers ranked #2 (all with the same point total ? )

I think since we're rounding to 5 digits for the Finder and Hider boards, then summing the results for the combined boards, that the combined boards should be rounded to 4 digits, not 5 and that will take care of this. I'll give that a shot.

If I'm getting to be a pain in the arse.. with these minor issues, sorry... let me know.. ha
dawg

Not at all, it's a good thing to correct all this. Thank you.

Tonight I changed rounding the Hider and Finder boards to 6 digits instead of 5 and kept the combined boards rounding to 5 digits. Again, this worked with my test data and hopefully this will work on production. You may note that I previously mentioned that I tried rounding to 6 digits and that didn't work. Then I was rounding Hider, Finder, and Combined boards to 6, this time Combined is to 5 so I think we're good. We'll find out for sure after the next statistics update completes.

[desert dawg]

Tonight I changed rounding the Hider and Finder boards to 6 digits instead of 5 and kept the combined boards rounding to 5 digits. Again, this worked with my test data and hopefully this will work on production. You may note that I previously mentioned that I tried rounding to 6 digits and that didn't work. Then I was rounding Hider, Finder, and Combined boards to 6, this time Combined is to 5 so I think we're good. We'll find out for sure after the next statistics update completes.

You fixed it.. looking good.. I got nothing to whine about today thanks...
I'm driving 300 miles Friday for breakfast on Saturday... gotta go get some caches out of this knee deep snow and freezing temps.... http://coord.info/GC43ARZ

[Corfman Clan]

You fixed it.. looking good.. I got nothing to whine about today thanks...
I'm driving 300 miles Friday for breakfast on Saturday... gotta go get some caches out of this knee deep snow and freezing temps.... http://coord.info/GC43ARZ

I'm glad to see this is finally put to rest. Have fun thawing out at the event.