Constant libbgs::streams::flags::NO_UPPER_HALF

pub const NO_UPPER_HALF: u8 = 0x02;

Stream will yield half as many elements as the default. Precisely, the stream will yield either $\chi$ or $\chi^{-1}$, but not both, for every $\chi \in F_{p^2}$. Even more precisely, for every $x$ the builder yields, the first non-zero coordinate is guarantied to be less than half the maximum of the its corresponding prime power.