Earlier quoted context omitted.
There's two variants of this (or, as the joke goes, for very big values of bit): Ternary Bonsai 27B uses ternary {−1, 0, +1} weights with FP16 group-wise scaling, giving a true 1.71 effective bits per weight. 1-bit Bonsai 27B uses binary {−1, +1} weights with the same group-wise scaling, giving 1.125 effective bits per weight.
this is a really dumb question, but how is -1 represented? is it a float? if so, how many bits is the float? I've never heard of a bit ever having more than two possible values
e.g. 5 trits (243 states) into a byte gives 1.6 bits per trit: https://compilade.net/blog/ternary-packing