date2jd	 - 	Julian day number from Gregorian date.
date2mjd	 - 	Modified Julian day number.
date2unixsecs	 - 	Number of seconds since 00:00:00 1 January 1970.
dayofmonth	 - 	Ordinal number of month in year.
dayofweek	 - 	Day of week.
dayofyear	 - 	Ordinal number of day in a year.
days2hms	 - 	Convert days into hours, minutes, and seconds.
daysinmonth	 - 	Number of days in a month.
daysinyear	 - 	Number of days in a year.
easterday	 - 	Easter day for a given year.
hms2days	 - 	Convert hours, minutes, and seconds to days.
hms2sec	 - 	Convert from hours, minutes and seconds to seconds.
isdate	 - 	True for valid dates (Gregorian calendar).
isjdate	 - 	True for valid dates (Julian calendar).
isleapyear	 - 	True for leap years.
istime	 - 	True for valid times.
jd2date	 - 	Gregorian calendar date from modified Julian day number.
jd2jdate	 - 	Julian day number to Julian calendar date.
jd2mjd	 - 	Modified Julian day number from Julian day number.
jdate2jd	 - 	Julian day number from Julian date.
mjd2date	 - 	Gregorian calendar date from Julian day number.
mjd2jd	 - 	Modified Julian day number from Julian day number.
monthofyear	 - 	Ordinal number of month in year.
sec2hms	 - 	Convert seconds to hours, minutes and seconds.
unixsecs2date	 - 	Number of seconds since 00:00:00 1 January 1970 to date.
weekofyear	 - 	Ordinal week number.
weeksinyear	 - 	Number of weeks in a year.
yearnum	 - 	Ordinal year number.