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Up Topic Rybka Support & Discussion / Rybka Discussion / Randomizer : minor curiousity
- - By gorlor (*) Date 2007-12-13 11:48 Edited 2007-12-13 12:04

I used the Randomizer to examine the following position:  1.e4 c6 2.d4 d5 3.e5 c5

I set up via the README instructions, and used a threshold of 25 centipawns, and played many games.  I was using a pair of randomized Rybka's in the Fritz GUI.  The engine match did not use the "alternate games" option.

I was slightly confused by the initial game continuations.

- White's 4th was always 4.Nf3.  Ok, so Rybka doesn't include any other candidates within the threshold.
- Black's 4th was initially Nc6.  Next game it chose cxd4.  Next game, then it chose cxd4 again. I had expected either a 3rd candidate or Nc6 again, but I guess technically it may increase the frequencies in a changed order.
- Next game it played cxd4 again.  Ok, now I'm confused.  This time I really did expect Nc6.
- The following game Nc6 was used, but why 3 x cxd4 before 2 x Nc6.
- I wasn't observing the games in real time.  I only looked at the game file afterwards.  I presume the GUI saved all games.

This is not a huge deal, just a minor curiousity.  I've still to experiment more to see if the behaviour is repeatable for other positions, etc.  I've searched the forum and haven't yet found anyone reporting likewise.

Am I missing something?  Or seeing a rare glitch?


Parent - By Kapaun (****) Date 2007-12-13 12:21
The randomizer seems to have some glitches anyway. For instance: If you take the starting position and give it to the randomizer, you may set the threshold to whatever you like - there will always be the same moves used.
Parent - - By Zruty (*****) Date 2007-12-13 12:39
Are you sure you swiched opening books off?
Parent - By Vasik Rajlich (Silver) Date 2007-12-13 12:47
Indeed, this sounds like an opening book issue.

Your description of what you expect is correct. When there are two candidate moves at a position within the threshold, they will alternate.

Parent - - By gorlor (*) Date 2007-12-13 13:40
My PGN file only contained the given opening line, and when I select this as the "Opening DB" (Fritz GUI -> "engine match" dialog), the selected books for the two randomized engines are greyed out.  Doesn't it just use one or the other?  I thought that using "Opening DB" made any book selection irrelevant.

I'll keep experimenting.  I only tried the randomizer as of yesterday.

My interest is to see the sort of middlegames that may arise from a given opening, assuming decent play by both sides.  Of course, game databases, etc. can help here too.  Just curious about the randomizer data.
Parent - - By gorlor (*) Date 2007-12-15 15:21
I've experimented some more, but without the expected behaviour.  There must be something wrong in my setup of the randomizer.

- I'm using Rybka 2.3.2a 32-bit single processor version.  I guess nothing special here.

- I tried using a centipawn value of 100 in order expect a lot of candidates

- suppose that the randomizer uses move "A" during game 1.  When it plays game 2 and reaches the same position, what should the analysis window show in terms of lines?  Only lines that do not start with move "A"?   i.e. when does the randomizer finalise its candidate list for a given position?  The first time it sees the position?  Or does it check for more candidates in later games?  I currently see normal looking analysis at all times.   i.e. suggests to me that I'm not executing a randomized Rybka, but just a normal Rybka.

- I've read over the readme instructions many times.  I can't see anything I'm doing wrong.
Parent - - By Vasik Rajlich (Silver) Date 2007-12-16 16:36
It does sound like you've disabled the opening book properly. Are you sure that the Rybkas which are playing this match are reading their config files? The GUI may be setting the engines' default paths to somewhere else. The name of a randomized Rybka should include the word "random" in it.

When a randomized Rybka reaches a position which was already reached in an earlier game, moves which have already been played are penalized by the centipawn margin in the search. Typically, if A has been played, and another alternative B exists, Rybka will just go straight for B in her search, stay there, and eventually play it.

Parent - - By Banned for Life (Gold) Date 2007-12-16 17:26
I'm not sure what GUI he's using, but most support the ability to display engine output (including the CB GUIs) and this will tell him if the randomizer option has been invoked.

Parent - - By gorlor (*) Date 2007-12-16 23:59
I'm using the CB GUI version that shipped with Deep Junior 9.  I called my two engines "Random1" and "Random2" in terms of the new folders and UCI name (the .exe file name wasn't changed).

The analysis output indicates a normal Rybka engine, and not the randomizer.  I agree that maybe the config is not getting read.  But why, I still don't know.  I'll keep playing around with it.  I acknowledge that others don't see this issue, and that it's something in my environment.
Parent - - By Uly (Gold) Date 2007-12-17 16:24
Are you sure that the file is named "rybka.config" and not "rybka.config.txt" or something else? Sometimes Windows hides these extensions.
Parent - - By gorlor (*) Date 2007-12-17 17:05
Fair point, but one that I checked earlier.  To create the doc, I right clicked in the folder and did a Windows "New -> Text Document", supplying the name "rybka.config".  I don't think Windows then appends ".txt".

I've tried cut n' pasting the exact "randomizer=10" line from the example (not that there's much to it!).  I've also copied the example PGN file contents.

Thanks for all suggestions.  I'll try going through the instructions on another PC shortly.  It's no huge deal.
Parent - - By noctiferus (***) Date 2007-12-17 17:13
yes it does. open the directory, go to  tools\ folder options\view, and uncheck "hide extensions".
Parent - - By gorlor (*) Date 2007-12-17 20:53
Doh!!!!  :-(

Fixed! :-)

I should have known better... sorry guys... that'll teach me for thinking I'd ruled out a possibility when I hadn't.  And Windows even changes the icon to show that a file is of type "text" or not...  aargh... I won't miss that again. :-)

The Randomizer output is interesting and useful.  Nice feature.

Thanks for all the help.
Parent - - By noctiferus (***) Date 2007-12-17 21:55
glad being of help :)
Parent - - By Uly (Gold) Date 2007-12-17 22:22
Hey! I was the one that had the idea of a wrong extension!

I deserve the credit!


Parent - By noctiferus (***) Date 2007-12-17 22:31
I was just suggesting him were to check  what happened.
no intention to deprive you of your merit! :)
Up Topic Rybka Support & Discussion / Rybka Discussion / Randomizer : minor curiousity

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