Minimum depth for null move

[pkumar]

As in many other programs, minimum depth for null move is 2 for crafty 24.1.

Code: Select all

    if (do_null && !pv_node && depth > 1 && !in_check &&
        TotalPieces(wtm, occupied)){
............code.....
      if (depth - tdepth - 1 > 0)
        value =
            -Search(tree, -beta, -beta + 1, Flip(wtm), depth - tdepth - 1,
            ply + 1, 0, NO_NULL);
      else
        value = -Quiesce(tree, -beta, -beta + 1, Flip(wtm), ply + 1, 1);
............more code.............
    }

What is wrong with minimum depth of 1? Apparently some nodes would be saved by dropping straight into Quiesce.

[hyatt]

if you use "1", how can you save anything? A normal search will drop directly into q-search. If you reduce the depth you STILL drop directly into the q-search. Nothing saved. Thats why I have the restriction...