Even if the parent node is the root node? In Jumbo I only break from the move loop at root when my 'stopSearch' flag is set, so that I do not ignore the results of the current iteration that were obtained so far. Returning alpha also at root would skip the whole iteration.RubiChess wrote: ↑Sat Dec 15, 2018 7:56 amYes, I have a global flag "IMMEDIATESTOP" that lets every parent node just return its alpha.Sven wrote: ↑Sat Dec 15, 2018 1:15 amDo you also use a flag indicating that the search is being stopped? If you don't then just returning alpha on detecting a timeout might be wrong since the direct parent node negates the score and performs a beta cutoff but then the parent's parent just continues with the next move after noticing that its current move has been refuted.
out of time in PVS
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Re: out of time in PVS
Sven Schüle (engine author: Jumbo, KnockOut, Surprise)
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Re: out of time in PVS
One thing that has not been mentioned is that if the best move of the previous iteration fails low and you have not yet found a satisfactory alternative, doing this may just lose. Adding time and continuing to search is a partial solution to this.
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Re: out of time in PVS
Usually, when you fail seriously low, trying to recover is a case of "too little, too late".
Rasmus Althoff
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Re: out of time in PVS
Probably, but you have to at least try.
I'm not sure that only breaking out of the search at the root is the best idea, although it would make things A LOT cleaner to code. But it also sounds like a really good way to get into time pressure. Myrddin's time management was created somewhat arbitrarily, but the only concession I made to root moves was to ensure that I had at least completed searching the first move in an iteration. After that, it's possible to break out at any time.
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Re: out of time in PVS
You are right, root search is different and keeps the best move and score found so far.Sven wrote: ↑Sat Dec 15, 2018 8:48 pmEven if the parent node is the root node? In Jumbo I only break from the move loop at root when my 'stopSearch' flag is set, so that I do not ignore the results of the current iteration that were obtained so far. Returning alpha also at root would skip the whole iteration.
Andreas