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The Great Gonzo
Help
24 Jun 03
###### The Great Gonzo
24 Jun 03

First off excellent site, I have four games going and have drawn in both my father in law and a friend.

My question is this. In general I understand that you gain points for winning matches and lose points for losing.

Could you please point me towards a detailed explanation of how the points are assigned.

Thanks
Greg

24 Jun 03

Hi there. Click on &quot;Help me!&quot; near the top right of your screen, then click on &quot;pop up help files&quot;. Number 9 of the FAQ helps to explain what you're after ðŸ™‚

T1000

###### The Great Gonzo
24 Jun 03

Thanks. That FAQ should be a top level link IMO.

24 Jun 03
1 edit

Just realised that while the above instructions deal with exactly how (ie the formula) for ratings calculation it doesn't really help to explain it in easy to understand terms (not easy for me to understand anyway!).

At the end of a game the points are decided by the ratings of the two players at the end of the game. If white has a much higher rating than black (eg 200+ points more) then white will receive (and black lose) very few points (since it is &quot;expected&quot; that white would win given the higher rating). If black were to win then white could expect to lose a large number of points (without closely reading through no. 9 of the FAQ I think that the maximum loss/gain regardless of rating is 32 points). Draws work in a similar fashion, but in this instance white would lose a few points and black would gain a few.

That's pretty brief and off the top of my head so not exhaustive and possibly not 100% accurate.

T1000

24 Jun 03

Originally posted by gregoftheweb
Thanks. That FAQ should be a top level link IMO.
I fink the whole of the help section will be getting an overhaul soon so watch this space....

###### RHP Code Monkey
25 Jun 03
1 edit

Originally posted by T1000
I fink the whole of the help section will be getting an overhaul soon so watch this space....
Lets hope so, in its current state, its nearly useless! ðŸ˜‰

-Russ

###### The winemaker
27 Jun 03

Originally posted by T1000
... I think that the maximum loss/gain regardless of rating is 32 points). ...T1000
That's correct as long as your rating is lower than 2100.
If your rating between 2100 and 2399 you may loose not more than 24 points in a game but there is only one person at the moment having that benefit ðŸ˜µ

If you are one of those who want to find out their potential win/loss in advance you can set up the following in Excel:

Type your current rating in cell A1 and the opponent's rating in A2

To calculate your rating in case of a win use the following formula in A3:
=ROUND(A1+IF(A1&lt;2099;32;IF(A1&lt;2399;24;IF(A1&gt;=2400;16)))*(1-(1/(10^((A2-A1)/400)+1)));0)

To calculate your rating in case you'll loose use the follwing formula in A4:
=ROUND(A1-IF(A1&lt;2099;32;IF(A1&lt;2399;24;IF(A1&gt;=2400;16)))*(1-(1/(10^(-(A2-A1)/400)+1)));0)

For an expected draw us the follwing in A5:
=(A3+A4)/2

Gotti

27 Jun 03

Originally posted by gotti2000
That's correct as long as your rating is lower than 2100.
If your rating between 2100 and 2399 you may loose not more than 24 points in a game but there is only one person at the moment having that benefit ðŸ˜µ

If you are one of those who want to find out their potential win/loss in advance you can set up the following in Excel:

Type your current rat ...[text shortened]... (10^(-(A2-A1)/400)+1)));0)

For an expected draw us the follwing in A5:
=(A3+A4)/2

Gotti
It doens't with work with me, I fill in (for example) my game against DigitGus wich I am winning: I fill in 1668 in A1 and 1699 in A2, I copy the formula in A3 and press enter...it gives me an error...ðŸ˜• I use Microsoft Office 2000, so I use Excel 2000.

Olav

###### The winemaker
27 Jun 03
4 edits

Originally posted by LivingLegend
[b]It doens't with work with me...
Hmm, I guess the problem is my generic translation, I didn't test this on an English system but only on a German one.
Well, the key is to change all the semicolons (ðŸ˜‰ to colons (,) because the default separator on UK/US systems is the colon as far as I know.
The following should work for you:
=ROUND(A1+IF(A1&lt;2099,32,IF(A1&lt;2399,24,IF(A1&gt;=2400,16)))*(1-(1/(10^((A2-A1)/400)+1))),0)

{To be more precise the separator in your formula must match the 'list separator' setting in the menu Start&gt;Control Panel&gt;Regional Settings&gt;Numbers&gt;list separator (2nd option from bottom)}

Another issue may be the language EXCEL is using. On my German Excel I have to use RUNDEN instead of ROUND and WENN instead of IF.
I can't believe that they even translated those keywords into German!

Anyway if you are using a dutch version you'll find the proper translation. However, if you are using Chinese ... ðŸ˜²ðŸ™„.
You can get a list of all functions in your language if you hit the function symbol (fx) in Excel which is between the sum symbol and the sort symbol.

Sorry, hope I didn't confuse you too much. If you've problems let me know.

gg

###### The Great Gonzo
27 Jun 03

I just wrote a quicky little web app to compute the ratings

http://www7.brinkster.com/obyrne/rhp_rc.htm

Now I'm not sure if the algorithm is quite right, because according to this tool I should have gotten 29 points for my latest victory and yet I got only 22...hmmm...grand conspiracy.

I don't want too much traffic over there so if someone wants to bring the little tool in house they can email me at gregoftheweb@hotmail.com.

###### The winemaker
28 Jun 03
1 edit

Originally posted by gregoftheweb
I just wrote a quicky little web app to compute the ratings

http://www7.brinkster.com/obyrne/rhp_rc.htm
Thanks for that. It makes life easier in an international environment. Nevertheless, your algorythm seems to be wrong.

When I use 1200 for MyRating and 1338 for OpponentRating I get 1222 for a win, 1190 for a lost game and 1206 for a draw. Which was the situation when you won against janwenting. Remember the new rating is calculated at the moment you finished the game. In most lists (e.g. Public Games) on RHP they display your current rating not the rating when you finished that particular game.

You may want to double-check your formula with mine and include that in your tool. It's quite cool!

Cheers,

gg

###### The Great Gonzo
28 Jun 03

Well I lifted the algorithm directly from the FAQ so if it is different I don't know where to get it.

View source on the page and look at it.

g

###### The winemaker
28 Jun 03
1 edit

I checked the formula in your code. It's correct as such but something weird happens with the power operator (^) in
nWinExpectancy = 1 / (10^((nOpponentRate-nMyRate)/400)+1)

The correct way to do exponential math in java-script is:
Math.pow(base, exponent)
You have to change the win expectancy code to following:

//set win expectancy
nWinExpectancy = 1 / (Math.pow(10,((nOpponentRate-nMyRate)/400))+1)

My2cents

gg

###### The Great Gonzo
30 Jun 03

There I go assuming the engine would do what I expected it should. Thanks.