I am reading BayesChess: A computer chess program based on Bayesian networks (Fernandez, Salmeron; 2008)
It is a chess-playing engine using Bayesian networks. The following is mentioned about the heuristic function in section 3.
Here the heuristic is defined in terms of 838 parameters.
There are 5 parameters indicating the value of each piece (pawn, queen, rook, knight, and bishop -the king is not evaluated, as it must always be on the board), 1 parameter for controlling whether the king is under check, 64 parameters for evaluating the location of each piece on each square on the board (i.e., a total of 786 parameters, corresponding to 64 squares × 6 pieces each colour × 2 colours) and finally 64 more parameters that are used to evaluate the position of the king on the board during the endgame.
The above sentence contains the parameters used by the heuristic function. But I didn't find the actual definition. What is the actual definition of the heuristic function?