Tag: Null Move

I improved MadChess 3.0 Beta’s Principal Variation Search (PVS) by consolidating two separate re-searches into one. In addition, I changed the null move implementation so it reduces the search horizon more aggressively if the current position’s static score far exceeds beta. Previously, if a PVS search failed high, the engine would confirm the fail high first by restoring beta from bestScore + 1 to its original value and re-searching. If that also failed high, it restored the search horizon from a reduced value to its original value and re-searched. If that failed high the engine took a beta cutoff. I… Continue Reading

I added null move search to MadChess 2.0 Beta. In addition, I limited the quiescence search to recaptures if the distance from the horizon is four or more moves. If the king is in check, all moves are searched. If not, and the distance from the horizon is four or more moves, only recaptures are searched (captures of the last piece that moved). These enhancements added 46 Elo to the playing strength of MadChess 2.0 Beta. MadChess 2.0 1950 : 800 (+271,=150,-379), 43.3 % vs. : games ( +, =, -), (%) : Diff, SD, CFS (%) BikJump v2.01 : 100… Continue Reading