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Ply depth mean

Posted: Sun Aug 02, 2009 2:47 am
by nanochess
Hi, I have a little doubt about ply depth means. My current view of it is as 1-ply depth exploration means one legal move of the computer without checking opponent moves, 2-ply depth means one move of computer and one move of opponent, 3-ply depth one computer, one opponent, one computer.

Also I'm reporting this number on Winboard POST information, is correct? or I should be saying 0-ply, 1-ply, 2-ply and reporting 0, 1, 2 instead of 1,2,3.

Re: Ply depth mean

Posted: Sun Aug 02, 2009 2:56 am
by xsadar
nanochess wrote:Hi, I have a little doubt about ply depth means. My current view of it is as 1-ply depth exploration means one legal move of the computer without checking opponent moves, 2-ply depth means one move of computer and one move of opponent, 3-ply depth one computer, one opponent, one computer.

Also I'm reporting this number on Winboard POST information, is correct? or I should be saying 0-ply, 1-ply, 2-ply and reporting 0, 1, 2 instead of 1,2,3.
Yes, you have a correct understanding of what a ply refers to. You should report depth as 1, 2, 3, ... plies. Zero plies would mean you didn't search anything, so you wouldn't have any search information to post.

Re: Ply depth mean

Posted: Sun Aug 02, 2009 5:25 am
by MattieShoes
xsadar wrote:
nanochess wrote:Hi, I have a little doubt about ply depth means. My current view of it is as 1-ply depth exploration means one legal move of the computer without checking opponent moves, 2-ply depth means one move of computer and one move of opponent, 3-ply depth one computer, one opponent, one computer.

Also I'm reporting this number on Winboard POST information, is correct? or I should be saying 0-ply, 1-ply, 2-ply and reporting 0, 1, 2 instead of 1,2,3.
Yes, you have a correct understanding of what a ply refers to. You should report depth as 1, 2, 3, ... plies. Zero plies would mean you didn't search anything, so you wouldn't have any search information to post.
Well, when ply==0, typically an engine runs a quiesence search, which might search nodes... If there are no q-search moves possible, then it wouldn't... Not trying to be pedantic, just pointing out that searching 0 ply might give a different value at the root than simply calling eval. :-)

Re: Ply depth mean

Posted: Sun Aug 02, 2009 5:28 am
by bob
nanochess wrote:Hi, I have a little doubt about ply depth means. My current view of it is as 1-ply depth exploration means one legal move of the computer without checking opponent moves, 2-ply depth means one move of computer and one move of opponent, 3-ply depth one computer, one opponent, one computer.

Also I'm reporting this number on Winboard POST information, is correct? or I should be saying 0-ply, 1-ply, 2-ply and reporting 0, 1, 2 instead of 1,2,3.
Your definitions are correct...