Aspiration Windows: Rubbish!

[ZirconiumX]

I have tested and tested, and I have one conclusion. They simply don't work for me.

I've watched many a test game where it searches normally, and is doing quite well, then suddenly gets a 'persistent phantom mate score' which pushes the window size to the point where it takes 5 seconds to perform a *one ply* search. This costs the program valuable time, and it loses.

I know this sounds like a search bug, but running with [-ValueInf, +ValueInf] works perfectly. It loses a ply of search, but never has a phantom mate score.

Matthew:out

[Gian-Carlo Pascutto]

I know this sounds like a search bug

Right.

[diep]

I know this sounds like a search bug

Right.

Worth nomination for post of the year isn't it?

[bob]

I have tested and tested, and I have one conclusion. They simply don't work for me.

I've watched many a test game where it searches normally, and is doing quite well, then suddenly gets a 'persistent phantom mate score' which pushes the window size to the point where it takes 5 seconds to perform a *one ply* search. This costs the program valuable time, and it loses.

I know this sounds like a search bug, but running with [-ValueInf, +ValueInf] works perfectly. It loses a ply of search, but never has a phantom mate score.

Matthew:out

When a 1 ply search takes 5 seconds, it is definitely a search issue.

[lucasart]

I know this sounds like a search bug

Right.

Worth nomination for post of the year isn't it?

Also for nomination
http://talkchess.com/forum/viewtopic.php?t=44306

[ZirconiumX]

So no-one pays any attention to what I have written. Fine.

It's not like anyone normally pays attention. Goodbye.

Lucas, that was fixed ages ago.

No wonder computer chess is dying. Because when they try to join, they get attacked. Marek, author of Sting had a great idea. But he has given up already. I will at least wait it out until the attack of the clones culture is gone.

Matthew:out

[gleperlier]

Hi Everyone,

Please Matthew is really yound, something like 12, so you'd better help him develop his skills, more than being sarcastic with him.

I guess it's really rare to have so young computer chess fans.

So again please, let him fly

Cheers,

Gab

[tpetzke]

Hi Matthew,

1 one ply search is easy to debug. Note the position where it happens and then for every move in the list look which one causes the trouble and why it is going so deep.

You can do this step by step, you will probably note something wrong with the code that lets you bang your head on the wall a few times. (Like one move captures the king or so)

This happened to me quite a few times.

Thomas...

[ZirconiumX]

Thomas,

I think it was 1 ply, I can't remember precisely.

It works perfectly with an infinite window search, but even with a window of +- 64 and doubling the window every time it falls out of bounds I sometimes get a mate score where there is no mate, and while it opens the windows and searches to resolve the fail low it uses up about 5 seconds. Now I test at 1 minute per game with no fischer increment, so it isn't that bad, but this usually happens at the late endgame where it can be game critical.

Matthew:out

[tpetzke]

Hi,

have you tried to disable the transposition table. If the research gets confused it might encounter some rubbish there.

Thomas...