Ignore:
Timestamp:
02/10/15 14:23:02 (9 years ago)
Author:
rlacroix
Message:

Add a new user defined calendar type.

A new calendar type "user_defined" is now available. This allows the users to create a custom calendar that we can configured to be suitable for planets other than the Earth.

An user defined calendar is always defined by two mandatory attributes:

  • day_length: the duration of a day, in seconds
  • and either:
    • month_length: an array containing the duration of each month, in days (the number of elements in the array is the number of months in a year)
    • or year_length: the duration of a year, in seconds (in that case, the calendar does not have months).

If the calendar has months (i.e. month_length attribute is set) and only in that case, it is possible to define leap years in order to compensate for the duration of an astronomical year not being a multiple of the day length. The leap years are defined by two mandatory attributes:

  • leap_year_month: the month to which the extra day will be added in case of leap year, expressed as an integer number in the range [1, numberOfMonths]
  • and leap_year_drift: the fraction of a day representing the yearly drift between the calendar year and the astronomical year, expressed as a real number in the range [0, 1).

Optionally, one can define the leap_year_drift_offset attribute to set the original drift at the beginning of the time origin's year, again expressed as a real number in the range [0, 1). If leap_year_drift_offset + leap_year_drift is greater or equal to 1, then the first year will be a leap year.

For example, the following configuration creates a Gregorian-like calendar:

<calendar type="user_defined" start_date="2012-03-01 15:00:00" time_origin="2012-02-28 15:00:00 + 1d" day_length="86400" month_lengths="(1, 12) [31 28 31 30 31 30 31 31 30 31 30 31]" leap_year_month="2" leap_year_drift="0.25" leap_year_drift_offset="0.75" />

Note that dates attributes must be written differently in the configuration file when using an user defined calendar without months:

  • if the year length is greater than the day length, the input format is year-day hh:min:sec instead of year-month-day hh:min:sec
  • if the day length is greater or equal to the year length, the input format is year hh:min:sec.

In all cases, it is still possible to use the date + duration notation to build a date (with both the date and duration parts being optional).

The Fortran interface has been updated accordingly so that xios_define_calendar can accept the new attributes necessary to define custom calendars.

File:
1 edited

Legend:

Unmodified
Added
Removed

  • XIOS/trunk/src/duration.hpp

    r501 r550  
    1313 
    1414      ///--------------------------------------------------------------- 
    15       typedef struct _duration 
     15 
     16      struct CDuration 
    1617      { 
    17          public : 
     18         public: /* static */ 
     19            static CDuration FromString(const StdString& str); 
    1820 
     21         public: 
    1922            /// Opérateurs /// 
    20             struct _duration & operator=(const struct _duration& duration); 
     23            CDuration& operator=(const CDuration& duration); 
    2124 
    22             friend StdOStream & operator<<(StdOStream & out, const struct _duration& duration); 
    23             friend StdIStream & operator>>(StdIStream & in , struct _duration& duration); 
     25            friend StdOStream& operator<<(StdOStream& out, const CDuration& duration); 
     26            friend StdIStream& operator>>(StdIStream& in , CDuration& duration); 
    2427 
    2528            /// Test /// 
    … …  
    2730 
    2831            /// Traitement /// 
    29             struct _duration & resolve(const CCalendar & calendar); 
    30             struct _duration & solveTimeStep(const CCalendar & c) ; 
     32            CDuration& resolve(const CCalendar& calendar, bool noNegativeTime = false); 
     33            CDuration& solveTimeStep(const CCalendar& c); 
    3134            /// Autres /// 
    3235            StdString toString(void) const; 
    3336 
    34          public: /* static */ 
    35  
    36             static struct _duration FromString(const StdString & str); 
    37  
    3837            /// Propriétés publiques /// 
    3938            double year, month, day, hour, minute, second, timestep; 
    40  
    41       } CDuration; 
     39      }; 
    4240 
    4341      ///--------------------------------------------------------------- 
    4442 
    45       const extern CDuration Year, Month , Week  , Day    , 
    46                              Hour, Minute, Second, NoneDu, TimeStep ; 
    47       ///--------------------------------------------------------------- 
    48  
     43      const extern CDuration Year, Month,  Week,   Day, 
     44                             Hour, Minute, Second, TimeStep, NoneDu; 
    4945} // namespace xios 
    5046 
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