julian-day-number ( $year $month $day -- n )
Calendar » Calendar facts

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Vocabulary
calendar

Inputs

$year	an integer
$month	an integer
$day	an integer

Outputs

n	an integer

Word description
Calculates the Julian day number from a year, month, and day. The difference between two Julian day numbers is the number of days that have elapsed between the two corresponding dates.

Warning
Not valid before year -4800 BCE.

See also
julian-day-number>date

Definition

USING: math ;

IN: calendar

:: julian-day-number ( $year $month $day -- n )
    14 $month - 12 /i :> $a $year 4800 + $a -
    :> $y $month 12 $a * + 3 - :> $m $day 153 $m * 2 + 5 /i +
    365 $y * + $y 4 /i + $y 100 /i - $y 400 /i + 32045 - ;