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UCI Help

Posted: Fri Jun 19, 2020 7:50 am
by mephisto
For UCI engines which in order is the most important?

A) Depth
B) Thread number of cores to be used.
C) Contemp factor
D) Ponder

Re: UCI Help

Posted: Fri Jun 19, 2020 8:58 am
by Ovyron
Depth - depends on the program's architecture, things like more knowledge or less selectivity can decrease depth, while making the program stronger. The Komodo engine showcases this with its Reduction and Selectivity settings, allowing the user to make it reach more depth or less depth, but modifying it weakens the engine.

Thread number of cores to be used - This will just be like giving more time to the engine. The more resources, the more time. Assuming a branching factor of 2, means at least 1 extra depth, which can equate to 50 to 70 elo, but you can never achieve a doubling of speed with a doubling of cores, this depends on good escalation.

Contempt factor - This would be the least important of the 4, because the strongest engine will have default settings as best, increasing or decreasing contempt will hurt performance against equal opponents. Stockfish's contempt is a special case in that it's more about avoiding draws by seeking variations that differ from default, which can be done without affecting strength to a certain degree. Very useful against weaker opposition.

Ponder - Third most important after Depth and number of threads. Ponder is regarded as a waste of resources, which could be used by something else, so it's a thing to use only if those resources wouldn't be used anyway. Sometimes it hurts (when the opponent doesn't play the expected move Ponder just erases useful info from the hash.)

Re: UCI Help

Posted: Fri Jun 19, 2020 1:15 pm
by mephisto
Hi Ovyron

Many thanks for your detailed reply which was very interesting.