Evaluation functions
n For chess, typically linear weighted sum of features
Eval(s) = w1 f1(s) + w2 f2(s) + … + wn fn(s)

n e.g., w1 = 9 with
   f1(s) = (number of white queens) –  (number of black
queens), etc.
n Caveat: assumes independence of the features
n Bishops in chess better at endgame
n Unmoved king and rook needed for castling
n Should model the expected utility value states with the
same feature values lead to.