def _get_cached_pdf( self ): if len( self.pdf_values ) == 0: cdf_line = MFnLineArray( xdata = self.x_values, ydata = self.cdf_values ) pdf = [] for x in self.x_values: pdf.append( cdf_line.get_diff( x ) ) return MFnLineArray( xdata = self.x_values, ydata = pdf ) else: return MFnLineArray( xdata = self.x_values, ydata = self.pdf_values )