Description
Flag a supplied astronomical-year interval that includes year zero.
Civil calendar arithmetic needs explicit year numbering, leap rules and index origins. A weekday mask or Gregorian component operation does not identify a timezone, working calendar or historical calendar reform.
Flag a supplied astronomical-year interval that includes year zero.
When to use this tool
Use Calendar Year Zero Omission Interval Loss when checking the stated weekday or Gregorian calendar convention.
How to use the tool and how it works
- Enter startAstronomical, endAstronomical. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read crossesZero, omittedYearCount. Inspect crossesZero before interpreting the associated values.
Flag a supplied astronomical-year interval that includes year zero. Require ordered endpoints; crossesZero uses start <= 0 <= end and omittedYearCount is one then, otherwise zero.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| startAstronomical | Start Astronomical | Required. Safe integer. |
| endAstronomical | End Astronomical | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| crossesZero | Whether the closed astronomical-year interval contains zero, including an endpoint. | Required. Boolean. |
| omittedYearCount | Omitted Year Count | Required. Safe integer. |
{
"input": {
"startAstronomical": -2,
"endAstronomical": 2
},
"output": {
"crossesZero": true,
"omittedYearCount": 1
}
}Limitations and assumptions
- This counts an omission convention, not an era conversion or a general interval-length calculation.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use an appropriate full calendar library and authoritative local rules when business days, historical dates or real scheduling matter.
References
Similar or alternative tools
- Date: Calendar Era Year Zero Policy
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