Function hc_wm_signal_mag 

fn hc_wm_signal_mag(
    te: f64,
    theta: f64,
    b0: f64,
    mwf: f64,
    r2p_meso: f64,
) -> f64

|complex hollow-cylinder GRE magnitude| at echo time te (s), angle theta (rad), myelin-water fraction mwf, and mesoscopic reversible rate r2p_meso.