It's very sad to hear this news. I never had the chance to meet Joseph in person, but I knew of him through his remarkable contributions to computer backgammon, and I deeply admired his work.
I'm truly sorry for this loss. My sincere condolences to his family and loved ones. On Fri, Apr 25, 2025 at 12:46 PM Øystein Schønning-Johansen < [email protected]> wrote: > It is with a real sorrow and heavy heart that I write this message. Today > I became aware of the tragic passing of Joseph Heled. His wife, Edna, has > informed us through Hans-Jürgen Schäfer the following: > > "I have to tell you that Joseph is no longer with us. A month ago he had a > fatal cardiac arrest while coming back from sports. Sudden, unexpected. We > are still in shock." > > I strongly feel that this is a really big loss to the backgammon community > and the community of backgammon programmers. Joseph was the inventor of so > many brilliant ideas that made it into the GNU Backgammon code base. He was > the main genius behind the true strength of GNU Backgammon. The neural > networks he trained more 25 years ago are still the best backgammon > evaluator systems around. This is due to the ingenious training method he > developed back then. He also found some of the fantastic smart methods to > speed up evaluation such that GNU Backgammon gained more or less > perfection. Let me list some of his clever ideas: > > - The training method of supervised learning on a fixed dataset from > rollouts. > - The benchmark method where move selection is the measured loss. > - The splitting of neural networks into position classes for race, > contact and crashed. > - The introduction of smaller pruning neural networks to find move > candidates in deeper plies. > - The table lookup of the exponential function which boosts the > sigmoid function. > - The trick of saving the inputs and the linear part of the first > layer from a previous position evaluation - such that the nn inputs > become mostly zeros - zeros are skipped such that the nn evaluation goes > faster. (This might be my personal favorite.) > > ... and many more. GNU Backgammon would not have been the same thing > without his insight and brilliance. > > In my communication with Joseph, he was really scientific. He always > checked his results before stating any conclusion and I respected his > findings as the ground truth. His insight - even when it came to something > seamingly simple like race positions - he had analysed things deeper than > anyone else. Our communications could be mail threads of nearly a hundred > messages. > > He could also be harsh and direct - especially here on this mailing list > if someone comes with a loose claim or something semi-scientific. In that > sense - he was not afraid of heated arguments. > > He also wrote a computer implementation of the Royal Game of Ur, which is > considered a precursor to backgammon - and like backgammon - a game that > combines both skill and luck. https://github.com/jheled/royalur > > In the later years he has studied a lot of backgammon and published some > interesting (and very theoretical) videos on youtube about backgammon race > doubles and backgammon rating systems. > https://www.youtube.com/@josephheled-pepster > > I strongly believe we have lost one of the best contributors to > computational backgammon. Thank you, Joseph, and rest in peace. And my > deepest condolences to Edna and other family members. > > -Øystein >
