def METHOD_NAME(n1, n2, txtf):
    """Calculate correlation"""
    corl = gs.read_command("r.covar", quiet=True, flags="r", map=(n1, n2))
    corl = corl.split("N = ")[1]
    corl = float(corl.split(" ")[1])
    gs.info(
        _("Correlation coeff of {} and {} {}").format(
            n1.split("@")[0], n2.split("@")[0], round(corl, 3)
        )
    )
    return ["Correlation coeff", n1, n2, corl]