Playing at weaker levels (observations/request)

[Volker Pittlik]

Some engines allow to adjust the playing strength. This is very good for me because even abn engine from the bottom of the rating lists are often too strong for me. Not to speak about the medium or upper range.

I dislike it when the engines move immediately (as Phalanx does) instead they should immitade a normal time usage (for example Shredder or ProDeo).

I made a few tests with Beowulf, Shredder, ProDeo and Homer. All of them at the weakest possible level. I took Xadreco, Surprise, Hoiches and GreKo to compare. Some observations so far:

Homer and BeoWulf are not getting really weak. Homer plays almost at the original level.

ProDeo and Shredder are doing really well. ProDeo seems to get really weak and managed it to lose all games in one round. (Think of the opponents!)

Xadreco is a bit delicate regarding the color. If it plays first white in a 2-game match it chrashes as black. If it plays black first there is no problem.

I'll add Yace to the test objects. Especially the "random mover" level.

I'm interested in more engines. So if you know some engines with an adjustable playing strength (especially if there is a Linux version) please let me know.

I'll report when the tests are finished.

Volker

[Jim Ablett]

Hi Volker,

Try this little hack for Phalanx, so it doesn't move instantly in 'easy level' mode'

Add to 'io.c' at line 1465.

Code: Select all

///  Io.c ///

         if( Flag.xboard )
                  puts("tellics resign");
               if( Color == WHITE )
                  puts("1-0 {Black resigns}");
               else   puts("0-1 {White resigns}");
            }
         }
           
    ////// pause before making move in 'easy level mode - JA ////////   
           
            if (Flag.easy && Bookout) {
            sleep(Otim/2200);    // may need to adjust a bit here   
            }       
    //////////////////////////////////////////////////////////                 
         
           
            printf("my move is "); printm( m, NULL );
         if( Flag.xboard )
         { printf("\n%i. ... ",(Counter+1)/2); gnuprintm(m); }
         puts("");
 

Jim.

[Fritz Grau]

In the Arena interface, there is an option to limit the strength of individual engines by assigning less CPU time to them, so they run as they would on a slower computer (minimum 1%, so if you have a 1GHz computer, it would run like on a 10MHz oldtimer). This should suffice at least for "lower class engines".

[Volker Pittlik]

In the Arena interface, ...".

Which unfortunately doesn't run on Linux. At least not without doing things not to recommend.

No, I'm not going to change my operating system.

Volker

[Volker Pittlik]

...
Try this little hack for Phalanx, so it doesn't move instantly in 'easy level' mode'

[..snip..].

Thanks Jim. Works fine so far. I'll report the results after some tests.


Volker

P.S. I guess the normal version of pretty old Phalanx is still strong enough for most chess players in the world. Maybe it should be reanamed to Kortchnoi .

[H.G.Muller]

I dislike it when the engines move immediately (as Phalanx does) instead they should immitade a normal time usage (for example Shredder or ProDeo).

This really seems a task for the GUI (so you could immediately use it on any engine in existence). It should simply delay displaying the move, putting the engine on a fast time control (with ponder off!)

Another solution would be an InBetween-like tool, which would translate the level, time and otime commands by dividing the specified times through a given factor, and delay relaying the move by an amount obtained by multiplying the actual time used by the same factor. Then you could use it on any engine in any GUI!

[Volker Pittlik]

...Another solution would be an InBetween-like tool, which would translate the level, time and otime commands by dividing the specified times through a given factor...

That would be very elegant! But if IIRC if one limits the time of the engine to 100 moves in a second for example and disable autoflag then the engines are still amazingly strong. At least stronger as in these special weak levels. But that depends on the engines too. Some get mad if one tries to play a game faster tahn in a minute. They think forever then:-)

Volker

[H.G.Muller]

Well, I guess some engines will not be able to handle arbitrarily fast time controls. I am guilty of that too; Joker always searches at least 6 ply, no matter how much time it has. I guess this should be considered a bug, and thre is really no good reason for it.

But an engine that can search only a few hundred nodes cannot be much good...

[Daniel Mehrmann]

Hi Volker,

yes, you're right, there is a bug in my reduce play strenght stuff.
I'll put a bugixversion soon on my page.

btw:

Homer doing a real reduce of play strenght. This means no ugly things like just play depth 1 or 1 second move.
So the oppoent should get the feeling it's real if homer really thinks 4 minutes on a move up to ply 16 but still give away a queen or just weaker positional moves

The completed search and eval process is real.

Best,
Daniel

[Volker Pittlik]

...
I'll put a bugixversion soon on my page.

I'll try that thing!

...Homer doing a real reduce of play strenght. This means no ugly things like just play depth 1 or 1 second move.
So the oppoent should get the feeling it's real if homer really thinks 4 minutes on a move...

Interesting. So far I tested ProDeo more closer and I found that strenght is increased in 2 or 3 big steps. Results will be published separately.

Btw: that test also has shown how nice a native Linux version is. ProDeo does not hang or freeze (used with wine): it "only" stays in RAM _from time to time_ until all available RAM is in use... This is not a problem specific to a certain engine. I guess wine simply does not work perfectly.

Volker