Module:Keppel date/doc
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This is the documentation page for Module:Keppel date
Converts the current (or provided) date to a Keppel date. Used by Template:Keppel date.
Algorithm
Begin with the following inputs:
year- The current year in the Gregorian calendar.
yday- The current day of the year in the Gregorian calendar.
First, define the following:
- Earth leap year
\text{year} \bmod 400 = 0 \text{year} \bmod 4 = 0\text{ and not }\text{year} \bmod 100 = 0
- Keppel leap year (schedule 1)
\text{year} \bmod 4 = 2
- Keppel leap year (schedule 2)
\text{year} \bmod 239 = 65
earthYearLength- If it is an Earth leap year, 366; else, 365.
yearLength- Start with 389.
- If it is a Keppel leap year (schedule 1), add one.
- If it is a Keppel leap year (schedule 2), add one.
rolloverOffset- If it is an Earth leap year, 79; else, 78.
To calculate the result:
year
\text{year} - 892
- If
ydayis less than 79, subtract one. yday
\frac{\text{yearLength} * (\text{yday} - \text{rolloverOffset})}{\text{earthYearLength}} \bmod{\text{yearLength}}
- If
ydayis less than or equal to zero, then addyearLength. lythryd
\lceil \frac{\text{yday}}{32} \rceil
day
\lfloor \text{yday} - (\text{lythryd} - 1) * 32 \rfloor