KDE_PI_adapt_norm       Adaptive normal PI estimate in the case of the
                        logarithmic transformation.
KDE_ln_PI               The PI kernel density estimate in the case of
                        the logaritjmic transformation.
KDE_power_PI            The PI kernel density estimate in the case of
                        the power transformation.
h_ln_PI                 Bandwidth for the PI estimator in the case of
                        the logarithmic transformation.
