Function pdf_with_progress 

pub fn pdf_with_progress<F>(
    field: &[f64],
    mask: &[u8],
    nx: usize,
    ny: usize,
    nz: usize,
    vsx: f64,
    vsy: f64,
    vsz: f64,
    bdir: (f64, f64, f64),
    tol: f64,
    max_iter: usize,
    progress_callback: F,
) -> Vec<f64>
where
    F: FnMut(usize, usize),

PDF with progress callback

Same as pdf but calls progress_callback(iteration, max_iter) each iteration.