Function gradient_weights_ilsqr 

fn gradient_weights_ilsqr(
    x: &[f64],
    mask: &[u8],
    nx: usize,
    ny: usize,
    nz: usize,
    vsx: f64,
    vsy: f64,
    vsz: f64,
    pmin: f64,
    pmax: f64,
) -> (Vec<f64>, Vec<f64>, Vec<f64>)

Gradient weights for streaking artifact estimation (Equation 15)