Evaluation Engine

DARKTHOUGHT decouples the chess knowledge as specialized scoring functions from the rest of the evaluation infrastructure. Before the start of each search, a root-node oracle [29] not only fills all piece-on-square tables (PSTs) afresh but it also selects appropriate scoring functions according to an extensive analysis of the root position. For each selected scoring function the oracle compiles a list of associated parameters and plugs both into the fully root-node programmable leaf-node evaluation function. In contrast thereto, limited hardware capabilities severly restricted the programmability of the evaluation in HITECH [27] that inspired the design of the evaluation engine in DARKTHOUGHT.

The evaluation infrastructure automatically tracks the state of the evaluation function (incl. PSTs) in order to detect any changes incurred by the oracle. In case of a change, the evaluation-dependent contents of all affected hash tables are cleared. Other important services of the evaluation infrastructure include the root-node programming interface and all-out management of the evaluation hash tables. Thus, the scoring functions can concentrate on their respective tasks without ever worrying or even knowing about hashing.


Created by Ernst A. Heinz, Thu Dec 16 23:28:11 EST 1999