Publius - public domain teaching engine

[Bart Weststrate]

Thanks for the kind words, Bart. I hope it takes much longer than in my previous engines to make this codebase write-only.

Pawel can you elaborate some more about this:

// Because pv-nodes don't use some pruning or
// reduction techniques, we cannot always reuse
// scores from the zero window nodes. Despite the
// same nominal depth, they represent more shallow,
// less precise search.
if (!isPv || (score > alpha && score < beta) ) {
if (!isRoot && !isExcluded)
return score;

I'm not sure if i get the concept. On !isPV (beta = alfa+1) nodes you can take any cutoff (lowerbound, upperbound, exact) and if PVnode you can only take the exact cutoff? Thanks in advance.

[PK]

On !isPV (beta = alfa+1) nodes you can take any cutoff (lowerbound, upperbound, exact) and if PVnode you can only take the exact cutoff?

Precisely. In the pv-nodes Publius switchess off many pruning techniques and uses smaller late move reduction. This means I sannot seriously assume that the same nominal depth from different node type actually means the same depth.