1. New and bigger neural network made from 1.2 billion position analyzed with Benjamin 1.1, estimated elo gain ~60.
2. Search changes, estimated elo gain ~40-50.
3. NNUE tuner parameter in Engine Settings. Changing the default of 100% to 125 will make Rebel even more aggressive, 150 up to the point of reckless, values lower than 100 will change the playing style to be more moderate. We tested the value 75 and it gave an extra 10 elo but it was preferred to leave the value at 100 exactly what the learner had created to keep the original Benjamin 1.1 playing style.
Fabien Letouzey for Fruit 2.1
Pawel Koziol for Growing Fruit
Chris Whittington for introducing me into NNUE, providing me with the necessary tools and writing the NNUE code.
This year (2022) it's 42 years ago I started chess programming, from REBEL 1.0 -> REBEL 12 and after my retirement from the competition and commerce (2003) the free hobby versions of ProDeo only gained about 200-250 elo through the years 2003-2021.
Inspiration (after 19 years) returned after a well known chess programmer offered his help with the implementation of the NNUE technique.
And the result speaks for itself, an improvement of 300-350 elo. It's my pleasure to realese REBEL 14, back to my brand name and its roots.