Author: Ratko V Tomic
Date: 08:30:28 11/06/99
Go up one level in this thread
>>Any excess piece would only drop the pawn maximum for that
>>side by 1
>
>My program used this fact and the fact that:
>an upper bound for the number of promoted white pieces is 2*the number of
>captures of black pieces+the number of captures of white pieces(I include pawns
>also as pieces).
>
This bound, by using "capture of black pieces" without distinction of black
pawns vs non-pawns (and similarly for white), isn't as tight as possible. If
white captures one black pawn with its pawn, white can indeed promote at most
twice, which is the example when your bound is tight. But if white pawn captures
1 black non-pawn, it can get at most 1 promotion (of the pawn which did the
capture), which is the case when your bound isn't as tight as possible.
It seems that a tighter bound on max white promotions would be a composite bound
which differentiates pawns and non-pawns in captures (in the target and the
source), expressed as follows:
1) Max 1 white promotion possible for
a) one black non-pawn capture by a white pawn or for
b) one white capture by a black pawn (of any white piece),
and
2) Max 2 white promotions possible for one black pawn capture
by a white pawn.
In the first example, white pawn captured a black pawn and got up to 2
promotions (bound part 2). In the second example, white pawn captures
one black non-pawn by its pawn (getting thus around its black pawn blocker) and
promotes this 1 pawn (bound part 1a). The bound part (1b): a black pawn captures
any white piece and gets out of the way of a white pawn it was blocking, so
white gets at most 1 promotion.
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.