fixed_gregorian: _Rata Die_ Conversion to and from Gregorian Years

In aion: Archaeological Time Series

Rata Die Conversion to and from Gregorian Years

Description

Convenient functions for conversion from and to rata die for a given Gregorian era.

Usage

fixed_from_BP(year, month, day)

fixed_to_BP(object)

fixed_from_BC(year, month, day)

fixed_to_BC(object)

fixed_from_BCE(year, month, day)

fixed_to_BCE(object)

fixed_from_AD(year, month, day)

fixed_to_AD(object)

fixed_from_CE(year, month, day)

fixed_to_CE(object)

fixed_from_b2k(year, month, day)

fixed_to_b2k(object)

Arguments

year	A numeric vector of years. If month and day are missing, decimal years are expected.
month	A numeric vector of months.
day	A numeric vector of days.
object	A RataDie object (see fixed()).

Details

The astronomical notation is used for Gregorian years (there is a year 0).

Value

• ⁠fixed_from_*()⁠ returns a RataDie object.

• ⁠fixed_to_*()⁠ returns a numeric vector of Gregorian years.

Author(s)

N. Frerebeau

References

Reingold, E. M. and Dershowitz, N. (2018). Calendrical Calculations: The Ultimate Edition. Cambridge University Press. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1017/9781107415058")}.

See Also

Other fixed date tools: arithmetic, as_date(), as_decimal(), as_fixed(), as_year(), fixed(), fixed_julian, format(), pretty()

Examples

## R 1.0.0
(y <- fixed(year = 2000, month = 02, day = 29, calendar = CE()))
as_date(y, calendar = CE())
as_year(y, calendar = CE())

## Create a vector of years BP (Gregorian)
## (every two years starting from 2000 BP)
(years <- seq(from = 2000, by = -2, length.out = 10))
## Convert years to rata die
(rd <- fixed(years, calendar = BP()))
## Convert back to Gregorian years BP
as_year(rd, calendar = BP())

## More convenient
(rd <- fixed_from_BP(years))
fixed_to_BP(rd)

aion documentation built on Oct. 4, 2024, 5:07 p.m.