ult, so whether it is negative
or positive. If it's positive, we predict one class, usually called +1, if it's negative,
we predict the other class, usually called -1. If the result is 0, by convention
the positive class is predicted, but because it's a floating point number that doesn't really
happen in practice. You'll see that sometimes in my notation I will not have a $b$. That's because
you can always add a constant feature to x to achieve the same effect (thought you would then need
to leave that feat