Computer Chess Club Archives




Subject: Caution K v KBN and lazy eval or futility

Author: Brian Richardson

Date: 13:53:46 05/14/00

Tinker's q-search lazy eval (material - max_pos_score)> beta return (like
standing pat?), and (material + queen+pawn) <= alpha return (quasi-futility?)
was working fairly well, until a K vs KBN endgame.  Since it was not getting to
the eval function, the special mating code was never used and Tinker ended up
with a 50 move draw...Now I check for opponent's pieces <= one minor and skip.

This was discussed in ICCA Vol 21 # 2 (Extended Futility and Dark Thought).  I
also have tried various regular futility, extended futility and razoring (as
outlined in the ICCA article), but they did not seem to help, at least given
Tinker's mix of searching algorithims.

Anyone else getting "good" results with them?

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