Tuesday, November 9, 2010

Algorithm 199

I'm blogging this just so I don't lose this useful reference to CACM Algorithm 199, a magic set of routines for converting between Gregorian (calendar) and Julian dates. Someday I'd love to read the original article and find out where all the magic numbers come from.

Posted by Jerry Callen at 5:13 PM

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4 comments:

  1. Paul KimpelMarch 31, 2015 at 10:36 AM

    http://pmyers.pcug.org.au/IndexedMultipleYearCalendar/Calgo_199.PDF

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  2. Paul KimpelMarch 31, 2015 at 10:38 AM

    Sorry, meant to include this link as well...

    http://www.digm.com/Resources/Gregory/Date-Manipulations-in-WFL.pdf

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  3. Jerry CallenMarch 31, 2015 at 11:29 AM

    Thanks for the links - I finally got to read the original paper! Sadly, it contains no explanations regarding the derivation of the magic numbers.

    It's been a while (since college, in the early '70s) since I've read any Algol.

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  4. Paul KimpelMarch 31, 2015 at 12:19 PM

    There's a section at the end of the second link that discusses how KDATE and KDAY work. You can skip the first part, as it is specific to the Unisys MCP job control language.

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