Function alcibiades::utils::perft

pub fn perft<T: MoveGenerator>(position: &mut T, depth: Depth) -> u64

Performs move path enumeration.

perft is a debugging function to walk the move generation tree of strictly legal moves and count all the leaf nodes of a certain depth, which can be compared to predetermined values and used to isolate bugs. In perft, nodes are only counted at the end after the last do_move. Thus "higher" terminal nodes (e.g. mate or stalemate) are not counted. Perft ignores draws by repetition, by the fifty-move rule and by insufficient material. By recording the amount of time taken for each iteration, it's possible to compare the performance of different move generators or the same generator on different machines.