Stockfish 4

[fern]

sorry, I do not understand. I believe or believed that a ply is one move for a side, two ply is a sequence of two moves, and so and so, then if they say 30 I consider there is a chain or sequence of 30 moves.
Please explain why it is no so in this case. I suppose you say that that number is not the number of ply but something else.


Fern

[zullil]

sorry, I do not understand. I believe or believed that a ply is one move for a side, two ply is a sequence of two moves, and so and so, then if they say 30 I consider there is a chain or sequence of 30 moves.
Please explain why it is no so in this case. I suppose you say that that number is not the number of ply but something else.


Fern

Ignore him. Stockfish is doing what you think, more or less.

[Henk]

sorry, I do not understand. I believe or believed that a ply is one move for a side, two ply is a sequence of two moves, and so and so, then if they say 30 I consider there is a chain or sequence of 30 moves.
Please explain why it is no so in this case. I suppose you say that that number is not the number of ply but something else.


Fern

if you start with depth = 30 or say level = 30 and you reduce or step with size 5 you get 30, 25, 20 .. 0. These are six ply (seventh ply is usually a pass or null move so I do not count it) one ply at level 30, one at level 25 etc. If you step with size 1 but only for the principal variation you get the normal 30 , 29, 28, ......0 that is thirty ply.

Of course stockfish does not do that but it only illustrates how simple it is to get such huge search levels. (Although LMR reductions look like this)

[Modern Times]

AMD Phenom II users need to go to
http://abrok.eu/stockfish/

to get an X64 compile that works, i.e.
stockfish_13082009_x64_modern.exe

The non-SSE4.2 x64 one is not in the download package from stockfish.org.

[fern]

Sorry, still above my head. What that reduction you mention is?
In any case my common sense say to me that if old dedicate units reached 5 or 6 ply in middle game, cannot be that modern engines running in hardware dozens of thousands of times faster do the very same thing.

In any case, it is a technical matter that that not touch me very deeply. I am beaten these days by 0 ply engines....

[JuLieN]

Sorry, still above my head. What that reduction you mention is?
In any case my common sense say to me that if old dedicate units reached 5 or 6 ply in middle game, cannot be that modern engines running in hardware dozens of thousands of times faster do the very same thing.

In any case, it is a technical matter that that not touch me very deeply. I am beaten these days by 0 ply engines....

Like Louis said. Henk is a bit confused. The 30 plies you mention are really 30 plies : Stockfish searches one ply, then, with iterative deepening, goes for a 2-plies search, then a 3-plies search, and so on, until it has no time anymore. And yes, it's a great achievement to reach such a depth in so little time. It means that Stockfish has a great move ordering and does a lot of pruning. In a clever way.

[Henk]

Sorry, still above my head. What that reduction you mention is?
In any case my common sense say to me that if old dedicate units reached 5 or 6 ply in middle game, cannot be that modern engines running in hardware dozens of thousands of times faster do the very same thing.

In any case, it is a technical matter that that not touch me very deeply. I am beaten these days by 0 ply engines....

LMR is late move reduction.

I estimate that these 30 moves search depth is equivalent to 12 (old school) moves.

Another way to look at it: If you only search a few variations very deep and the remaining moves far less deep then it is easy to make it to level 30.
Of course you only show the variations to the user that are searched deep.

[Thomas Lagershausen]

Dear Mr. Costalba & team

Thx a lot for this superstrong chessprogram.

You made the world a magic place.

Glory days

[fern]

Well, yes, that is what I thought, but this pal here instilled me some doubts because after all I am not a technician in this field.....

fern

[Marek Soszynski]

The http://stockfishchess.org/download/ page boasts "Precompiled binaries for all operating systems." It should be made clearer that Linux compilations can be found by following the "Dev Versions" link.