Wikipedia states that:

An evaluation function, also known as a heuristic evaluation function or static evaluation function, is a function used by game-playing computer programs to estimate the value or goodness of a position (usually at a leaf or terminal node) in a game tree.

Is "goodness" an actual term in use in this context, or should it more properly be something like "perceived optimality"?

I ask because, for instance, in Combinatorial Game Theory, a lighthearted term such as "loopy" is preferred by some mathematicians (Demaine) over the more serious term "cyclic" (Fraenkel).

On a related note, is the use of "position" instead of "node" preferred here as an acknowledgment of the heuristic nature of evaluation functions? (My understanding is that "position", "node" and "game" may all be interchangeable in certain contexts.)


1 Answer 1


Yes, "goodness" is a common description of the value generated by an evaluation function. For example, "Artificial Intelligence" p. 77; "Knowledge-Free and Learning-Based Methods in Intelligent Game Playing" p. 15; "Tenth Scandinavian Conference on Artificial Intelligence" p. 125; and "Algorithms and Networking for Computer Games" p. 80.

The "position" is to the complete state of the game at some instant. A single position includes the locations of every piece on a game board at that instant, and also includes a few other bits of information -- who's turn it is; whether castling is still a legal option; etc.

I suspect that "the position" is a synecdoche, referring to the total state by a small part, the physical location (physical position) of some piece on the game board, based on earlier usage in military tactics of "positioning" troops relative to natural cover or relative to enemy troops.


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