Author: Bruce Moreland
Date: 17:24:24 12/05/00
Go up one level in this thread
On December 05, 2000 at 16:46:17, Severi Salminen wrote: >Hi! > >Check out this position: > >[D]rnbqkbnr/ppp2ppp/8/3pp3/3PP3/8/PPP2PPP/RNBQKBNR w > >With futility pruning my program does this: > > > Time Depth Score Nodes PV > 0 1 -0.14 175 Be3 > 0.00 2 -0.19 1851 Be3 Be6 > 0.11 3 -0.11 7755 Nf3 Bb4+ Bd2 dxe4 Bxb4 exf3 dxe5 Qxd1+ Kxd1 >fxg2 Bxg2 > 0.33 4 -0.14 22227 Nf3 exd4 Qxd4 Be6 > 0.98 5 0.00 67477 dxe5 dxe4 Qd7+ Qxd7 > 3.07 6 -0.12 324618 Nf3 Bg4 Be2 Bxf3 Bxf3 Bb4+ > 12.41 7 0.00 1515184 Qh5 dxe4 Qxe5+ Qe7 Qxc7 Qxc7 > 33.06 8 -0.09 4203195 dxe5 dxe4 Qxd8+ Kxd8 Bc4 Nc6 Bf4 Bb4+ > >And without: > > Time Depth Score Nodes PV > 50 1 -0.14 175 Be3 > 0.05 2 -0.19 1851 Be3 Be6 > 0.16 3 -0.11 7850 Nf3 Bb4+ Bd2 dxe4 Bxb4 exf3 dxe5 Qxd1+ Kxd1 >fxg2 Bxg2 > 0.44 4 -0.14 22555 Nf3 exd4 Qxd4 Be6 > 1.10 5 -0.09 73064 Nf3 dxe4 Nxe5 Bb4+ c3 > 2.85 6 -0.12 306521 Nf3 Bg4 Be2 Bxf3 Bxf3 Bb4+ > 9.61 7 -0.07 1212161 dxe5 dxe4 Qxd8+ Kxd8 Bc4 Bb4+ Nd2 > 29.33 8 -0.09 3947537 dxe5 dxe4 Qxd8+ Kxd8 Bc4 Nc6 Bf4 Bb4+ > >Why the h?%l is the one without futility pruning faster and has less nodes? I >use futility margin of 2 pawns. >My futility code is something like: (I prune check now also...) > >if(depth==1) > if(futility_condition(Moves[k].value)<=alpha) > continue; > >the futility_condition() returns the current material balance + the material >gain of the move+ 200. > >Any ideas? > >BTW. Does my node counts look reasonable? I'm using MVV/LVA ordering in qsearch >+ nullmoves (R=2). > >Severi It switched moves in a later ply in the one where you prune, and this costs nodes. It is not possible to determine whether a pruning technique is good or bad based upon one position. Who may as well decide a coin is lucky or unlucky depending upon whether it comes up heads the first time. bruce
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.