def dispersion(vmin, dx, fc, coeff=2.0):
    """Compute maximum dt for a stable simulation.

    Parameters
    ----------
    vmin: float
        Minimum velocity of the medium
    dx: float
        Grid discretization.
    fc: float
        Central (peak) frequency of the source wavelet.
    coeff: float
        Coefficient to compute the maximum frequency of the wavelet:
        fmax = coeff * fc.

    Returns
    -------
    dt_stable: float
        Maximum temporal discretization.
    """

    fmax = coeff * fc
    dx_no_dispersion = vmin / fmax / 6.0
    if dx > dx_no_dispersion:
        print('The simulation will show dispersion!')

    return dx_no_dispersion