(iteration+depth) TT replacement policy.

[Aleks Peshkov]

Just caught an idea using (iteration+depth) as replacement metrics. The most important records should be visited in every iteration of iterative deepening, so the deepest entries would still have priority between most recent ones.

But outdated unused deep entries would be flushed out very fast.

[Rein Halbersma]

How would that look in code?

[mcostalba]

This may be an interesting idea to play with. Currently engines use aging (in case of SF is called 'generation' and is incremented every new search) to prefer entries from current search to older ones.

This would be a kind of tradeoff, not so strong as new generation, but still something to add to depth.

[Aleks Peshkov]

Iteration counter grows very fast at the beginning of new generation, so unused entries would still be flushed out except the deepest ones.