def to_julian_date(self):
        """
        Convert Datetime Array to float64 ndarray of Julian Dates.
        0 Julian date is noon January 1, 4713 BC.
        http://en.wikipedia.org/wiki/Julian_day
        """

        # http://mysite.verizon.net/aesir_research/date/jdalg2.htm
        year = np.asarray(self.year)
        month = np.asarray(self.month)
        day = np.asarray(self.day)
        testarr = month < 3
        year[testarr] -= 1
        month[testarr] += 12
        return (day +
                np.fix((153 * month - 457) / 5) +
                365 * year +
                np.floor(year / 4) -
                np.floor(year / 100) +
                np.floor(year / 400) +
                1721118.5 +
                (self.hour +
                 self.minute / 60.0 +
                 self.second / 3600.0 +
                 self.microsecond / 3600.0 / 1e+6 +
                 self.nanosecond / 3600.0 / 1e+9
                 ) / 24.0)
def to_julian_date ( self ) : year = np . asarray ( self . year ) month = np . asarray ( self . month ) day = np . asarray ( self . day ) testarr = month < 3 year [ testarr ] -= 1 month [ testarr ] += 12 return ( day + np . fix ( ( 153 * month - 457 ) / 5 ) + 365 * year + np . floor ( year / 4 ) - np . floor ( year / 100 ) + np . floor ( year / 400 ) + 1721118.5 + ( self . hour + self . minute / 60.0 + self . second / 3600.0 + self . microsecond / 3600.0 / 1e+6 + self . nanosecond / 3600.0 / 1e+9 ) / 24.0 )
Convert Datetime Array to float64 ndarray of Julian Dates.
        0 Julian date is noon January 1, 4713 BC.
        http://en.wikipedia.org/wiki/Julian_day