pub fn direction_from_uvtw(uvtw: [i32; 4]) -> Result<[i32; 3], CrystalError>Expand description
Three-index direction [U V W] = [u - t, v - t, w] of the Miller-Bravais
direction [uvtw] (see the module docs for the convention).
ยงErrors
CrystalError::InvalidMillerBravais unless u + v + t = 0, or if an
index overflows i32.