[drougge]

This seems interesting, but I got stuck fairly early on when I read "all 32,385 possible input combinations". There are two 8 bit numbers, 16 totally independent bits. That's 65_536 combinations. 32_285 is close to half that, but not quite. Looking at it in binary it's 01111110_10000001, i.e. two 8 bit words that are the inverse of each other. How was this number arrived at, and why?

Looking later there's also a strange DAC that gives the lowest resistance to the least significant bit, thus making it the biggest contributor to the output. Very confusing.

[dahart]

Is that the number of adds that don’t overflow an 8-bit result?

On that hunch, I just checked and I get 32896.

Edit: if I exclude either input being zero, I get 32385.

You also get the same number when including input zeros but excluding results above 253. But I’d bet on the author’s reason being filtering of input zeros. Maybe the NN does something bad with zeros, maybe can’t learn them for some reason.

[jtsiskin]

Interesting puzzle. 32385 is 255 pick 2. My guess would be, to hopefully make interpretation easier, they always had the larger number on one side. So (1,2) but not (2,1). And also 0 wasn’t included. So perhaps their generation loop looks like [[(i,j) for j (i-1 -> 1) for i (256 -> 1)]

[joshribakoff]

You are potentially conflating combinations with permutations.