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Symmetry454 time unit classes

Source: R/cal_sym454.R
calendar_sym454.Rd

Time unit constructors for the Symmetry454 calendar system. These units can be used with linear_time() to create custom time representations.

Usage

cal_sym454

Format

A civil-based calendar containing Symmetry454 time units.

Details

The Symmetry454 calendar (Sym454) is a perennial solar calendar proposed by Dr. Irv Bromberg. It preserves the traditional 12-month structure and 7-day week, with months arranged in a symmetrical 4-5-4 week pattern per quarter. Every month starts on Monday and has a whole number of weeks, meaning no month ever contains a partial week.

The following time units are available in the Symmetry454 calendar (cal_sym454$).

  • year(): Year unit

  • month(): Month unit

  • week(): Week unit

  • day(): Day unit

  • hour(): Hour unit

  • minute(): Minute unit

  • second(): Second unit

  • millisecond(): Millisecond unit

Leap years

Rather than intercalary days, Symmetry454 uses a leap week appended to December once every 5 or 6 years, making December a 5-week month in leap years. A year is a leap year if (52 * year + 146) %% 293 < 52.

This yields a mean year of 365 + 71/293 days (≈ 365 days, 5 hours, 48 minutes, 56.5 seconds), intentionally slightly shorter than the mean northward equinoctial year.

See also

linear_time() for creating linear time points, and https://en.wikipedia.org/wiki/Symmetry454 for more calendar details.

Examples

# Create a custom time representation using Symmetry454 units
linear_time(
  Sys.time(),
  chronon = cal_sym454$week(1L)
)
#> <mixtime[1]>
#> [1] 2026-Apr-W2