Module:Keppel date/doc: Difference between revisions

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Converts the current (or provided) date to a Keppel date. Used by Template:Keppel date.

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 Converts the current (or provided) date to a Keppel date.
 Used by [[Template:Keppel date]].
-==Algorithm==
-Begin with the following inputs:
-;<code>year</code>
-:The current year in the Gregorian calendar.
-;<code>yday</code>
-:The current day of the year in the Gregorian calendar.
-First, define the following:
-;Earth leap year
-<math mode="display">\text{year} \bmod 400 = 0</math>
-<math mode="display">\text{year} \bmod 4 = 0\text{ and not }\text{year} \bmod 100 = 0</math>
-;Keppel leap year (schedule 1)
-<math mode="display">\text{year} \bmod 4 = 2</math>
-;Keppel leap year (schedule 2)
-<math mode="display">\text{year} \bmod 239 = 65</math>
-;<code>earthYearLength</code>
-:If it is an Earth leap year, 366; else, 365.
-;<code>yearLength</code>
-: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.
-;<code>rolloverOffset</code>
-:If it is an Earth leap year, 79; else, 78.
-To calculate the result:
-;<code>year</code>
-<math mode="display">\text{year} - 892</math>
-:If <code>yday</code> is less than 79, subtract one.
-;<code>yday</code>
-<math mode="display">\frac{\text{yearLength} * (\text{yday} - \text{rolloverOffset})}{\text{earthYearLength}} \bmod{\text{yearLength}}</math>
-:If this is less than or equal to zero, add <code>yearLength</code>.
-;<code>lythryd</code>
-<math mode="display">\lceil \frac{\text{yday}}{32} \rceil</math>
-;<code>day</code>
-<math mode="display">\lfloor \text{yday} - (\text{lythryd} - 1) \times 32 \rfloor</math>
-<includeonly>[[Category:Modules: tesinormed]]</includeonly>