Using the ISO 8601 standard is a good idea; while a lot of transportation companies (notably railways in North America) treat Sunday as day 0, I have no problem with having it be 7.
-Marc -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of xypron Sent: Friday, November 21, 2008 2:46 AM To: [email protected] Subject: RE: [Help-glpk] Time conversion functions Hello Marc >>Can you add a DayOfWeek(t) which returns a number 0 to 6, with 0=Sunday, >>1=Monday, etc. ISO 8601 defines a week date see http://en.wikipedia.org/wiki/ISO_week_date http://en.wikipedia.org/wiki/ISO_week_date Sunday has to be 7 to comply with ISO 8601 and to allow correct sorting. >>Personally, I prefer the way that Excel and many other packages model >>time: It is the number of days (as a 64-bit "real" number) from some >>base time, so 0.5 represents 12 hours from the base time. It makes >>differences very easy to calculate. Calculating with seconds instead of days is not more difficult but avoids rounding errors. Anyway the SI unit of time is seconds. Best regards Xypron -- View this message in context: http://www.nabble.com/Time-conversion-functions-tp20549985p20616523.html Sent from the Gnu - GLPK - Help mailing list archive at Nabble.com. _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk ---------------------------------------------------------------------------- This e-mail and any attachments may be confidential or legally privileged. If you received this message in error or are not the intended recipient, you should destroy the e-mail message and any attachments or copies, and you are prohibited from retaining, distributing, disclosing or using any information contained herein. Please inform us of the erroneous delivery by return e-mail. Thank you for your cooperation. ---------------------------------------------------------------------------- _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
