could someone explainSF's move ordering to me ?

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MahmoudUthman
Posts: 237
Joined: Sat Jan 17, 2015 11:54 pm

could someone explainSF's move ordering to me ?

Post by MahmoudUthman »

-what is FromToStats , I couldn't find anything about it on CPW ? (by the way should this be "on" or "at" CPW?)
-what are fmh/fm ,fmh2/fm2 "follow-up moves" for ? and do they have another name on CPW "both CPW's & CCC search don't returns any useful result"?
-why is it only using history in ordering non-capture evasions ?
mjlef
Posts: 1494
Joined: Thu Mar 30, 2006 2:08 pm

Re: could someone explainSF's move ordering to me ?

Post by mjlef »

MahmoudUthman wrote:-what is FromToStats , I couldn't find anything about it on CPW ? (by the way should this be "on" or "at" CPW?)
-what are fmh/fm ,fmh2/fm2 "follow-up moves" for ? and do they have another name on CPW "both CPW's & CCC search don't returns any useful result"?
-why is it only using history in ordering non-capture evasions ?
I suggest you study the Stockfish code to see what it all means. Sometimes names can be deceptive.

History tables are used in many programs to help better order non-tactical moves (non captures and non promotions).

FromToStats: as the name suggests, these history values are indexed by the from and to squares (like g1f3).
fmh, fm2: these are history tables indexed first by the piece and to position 2 ply ago (same side moving as now) then by the current piece and to position. fm means followup move. For example, if we played say pawn to e4 in the past and found that a good followup is knight to g3. fm2 is the same idea, only using as an index the move the same side played 4 plies ago (2 moves for that side).
the cm tables in Stockfish are Counter Move tables. So instead of indexing by the last move the current side made, it uses the last move the opponent made.
Dirt
Posts: 2851
Joined: Wed Mar 08, 2006 10:01 pm
Location: Irvine, CA, USA

Re: could someone explainSF's move ordering to me ?

Post by Dirt »

MahmoudUthman wrote:by the way should this be "on" or "at" CPW?
Either is correct but "on" is more usual.
Deasil is the right way to go.