"It just isn't conceivable that you can design a program strong enough to beat players like me."

February 25, 2018

Android UCI engine update: Stockfish 9

The long awaited ninth fish was finally released after TCEC-9, thanks to latest fruitful patches adding the utilization of the contempt factor. This number defines how positive (or negative) the engine will interpret its evaluation. More contempt means more optimism and less contempt means more desperation for an engine. By definition, contempt factor can convert draws to wins against a weaker engines but it can also cause losses instead of draws, while forcing for a win.

By the end of Janary, the official SF9 has been released on Stockfish website. It has included Alexei Chernakoff's Android builds that i share below. The choice of the Stockfish team made us extremely happy and proud of what he achieved.

GET Stockfish 9.ACH (OFFICIAL) for arm7 (Jan-31th, CRC32: 23404375) and arm8

After first tests, arm7 build has been found to perform worse than expected due to incompatibility between latest patches and heavy PGO+LTO optimizations used by the compiler. Arm8 builds were healthy but arm7 delivered less than +60 ELO vs SF8.

Therefore, following alternatives came quickly in a few days during first week of February.

GET Stockfish 9.ACH for arm7 (2nd build on Feb-2nd, probably without PGO/LTO, CRC32 = D38AD094)
GET Stockfish 9.ACH for arm7 (3rd build on Feb-2nd, fixed PGO, CRC32 = 251627CA)
GET Stockfish 9.ACH for arm7 (4th build on Feb-7th, noPGO?, CRC32 = 25D1EE16)
GET Stockfish 9.ACH for arm7 (5th build on Feb-7th, fixed PGO, no LTO, CRC32 = 65FEB516)

I'd already chosen the 3rd build for Rapidroid before the 4th and 5th came out and didn't change it afterwards because it had played a lot and its performance was satisfying (+60 to 90 ELO depending on the progression of the rounds). So, it's up to you to decide which one suits you best.

One thing is sure: More nps didn't mean higher ELO this time.

In case of trouble downloading from PC, use your mobile or refer to THIS POST.

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