def jcal2jd(year, month, day):
    """Julian calendar date to Julian date.

    The input and output are for the proleptic Julian calendar,
    i.e., no consideration of historical usage of the calendar is
    made.

    Parameters
    ----------
    year : int
        Year as an integer.
    month : int
        Month as an integer.
    day : int
        Day as an integer.

    Returns
    -------
    jd: int
        Julian date.
    """
    year = int(year)
    month = int(month)
    day = int(day)

    jd = 367 * year
    x = ipart((month - 9) / 7.0)
    jd -= ipart((7 * (year + 5001 + x)) / 4.0)
    jd += ipart((275 * month) / 9.0)
    jd += day
    jd += 1729777
    return jd
dataset/ETHPy150Open mne-tools/mne-python/mne/externals/jdcal.py/jcal2jd/original