calendar::lunar::algo3 Namespace Reference

Functions
auto	calc_lunar_year (int32_t year) -> common::LunarYear
	Calculate the lunar year information for the given year.

Variables
constexpr int32_t	START_YEAR
	The first supported lunar year.
constexpr int32_t	END_YEAR
	The last supported lunar year.
constexpr std::array< uint32_t,(END_YEAR - START_YEAR+1)>	LUNAR_DATA
	The encoded binary data for each lunar year. Info for a year is stored in a uint32_t.
const auto	bounds
	The bounds of the algorithm, i.e. the supported range of lunar and Gregorian dates.

Function Documentation

calc_lunar_year()

auto calendar::lunar::algo3::calc_lunar_year ( int32_t year ) ->common::LunarYear

inlinenodiscard

Calculate the lunar year information for the given year.

Attention

The input year should be in the range of [START_YEAR, END_YEAR].

Parameters

year	The Lunar year. 阴历年份。

Returns

The lunar year information. 阴历年信息。

Variable Documentation

bounds

const auto calendar::lunar::algo3::bounds

inline

The bounds of the algorithm, i.e. the supported range of lunar and Gregorian dates.

END_YEAR

int32_t calendar::lunar::algo3::END_YEAR

inlineconstexpr

The last supported lunar year.

LUNAR_DATA

std::array<uint32_t, (END_YEAR - START_YEAR + 1)> calendar::lunar::algo3::LUNAR_DATA

inlineconstexpr

The encoded binary data for each lunar year. Info for a year is stored in a uint32_t.

See also

https://www.hko.gov.hk/sc/gts/time/conversion.htm

Espenak and Meeus, NASA/TP-2006-214141, Section 2.7, equations (11)-(25); historical source for 398 retained non-HKO entries. https://ntrs.nasa.gov/citations/20070003587

Note

Gregorian dates use a baked hybrid basis: 1901–2099 preserves algo1's HKO labels; every other year was generated from algo2's fixed-east-eight civil rendering. No one historical time-zone rule describes the whole table. 公历日期基准是混合的：1901 至 2099 年保留 algo1 的香港天文台日期标记，其余年份由 algo2 的固定东八区民用时间生成； 不存在一条历史时区规则可以概括整张表。

Provenance (baked table – #70)

• Generator: statistics/lunar_calendar.ipynb (encode cells: HKO years 1901–2099 via algo1 / HKO table; all other years via live algo2 — see algo2.hpp).
• All 401 non-HKO values (1600–1900 ∪ 2100–2199) re-encode identically under live algo2. Re-bake through the same notebook whenever its time-scale dependencies change.
• The 199 HKO entries (1901–2099) carry no ΔT dependence; they are algo1's table verbatim. Their retained HKO identity record is src/test/provenance/hko/2026-08-25/. Retained under owner risk acceptance; upstream permission was not obtained and no permission is claimed. These HKO-derived words remain under their source terms and outside the project MIT grant. Full-array re-encode against live algo2 is not zero-diff: the six known years 1914/1915/1916/1920/2057/2097 diverge (see diff_test.cpp / #64). This block is a provenance note, not a data fix: do not edit any of the 600 values here without a deliberate re-bake and review.
• Read-only re-verification: run the "重烤对账" code cell at the end of statistics/lunar_calendar.ipynb. It re-encodes the re-bakeable subset and prints a mismatch count against this array. A zero count confirms that subset matches. The cell never writes this header back.
• External oracle for a sampled subset of years: src/test/lunar/algo3_ytliu0_golden_test.cpp (ytliu0 ChineseCalendar, see that file's provenance head). Dual-table / live-algo2 internal checks: src/test/lunar/algo3_test.cpp.

START_YEAR

int32_t calendar::lunar::algo3::START_YEAR

inlineconstexpr

The first supported lunar year.