Function rgsl::coupling_coefficients::_6j

pub fn _6j(
    two_ja: i32, 
    two_jb: i32, 
    two_jc: i32, 
    two_jd: i32, 
    two_je: i32, 
    two_jf: i32
) -> f64

This routine computes the Wigner 6-j coefficient,

{ja jb jc jd je jf}

where the arguments are given in half-integer units, ja = two_ja/2, ma = two_ma/2, etc.