Function volume 

pub fn volume<T: Copy + Add<Output = T> + Sub<Output = T> + Mul<Output = T>>(
    a: [[T; 3]; 3],
    dim: usize,
) -> Result<T>

Signed determinant for a one-, two- or three-dimensional cell.

Upstream: treams.lattice.volume and, in two dimensions, treams.lattice.area.