Fivefold Tithi family

personal.tithi-family

Tithi ordinal cycles through Nanda, Bhadra, Jaya, Rikta, and Purna families.

Assurance

Level	Current statement
Documented and traceable	Yes — the canonical record includes the process and a worked example.
Regression or reproduction checked	Linked to 2 repository test file(s).
Independently source-supported	Not recorded as independently verified. The disclosed provenance state remains authoritative.

Computation method

Method type: formula

Extract the Paksha-local Tithi ordinal from the final word of the name and map its repeating fivefold remainder to a family.

Process

1. Read the final token so Paksha prefixes and named Ekadashi prefixes do not affect classification.
2. Normalize accepted aliases including Pratipada, Shashti, and Amavasya.
3. Convert to an ordinal from 1 through 15.
4. Map 1/6/11 Nanda, 2/7/12 Bhadra, 3/8/13 Jaya, 4/9/14 Rikta, and 5/10/15 Purna.
5. Let the selected activity profile decide whether that family is preferred, penalized, neutralized, or excluded.

Formulae

Fivefold family index

family_index = (t-1) mod 5

• t: Paksha-local Tithi ordinal 1 through 15
• family order: Nanda, Bhadra, Jaya, Rikta, Purna

Worked example

Shukla Navami

Inputs

• Final token: Navami
• Tithi ordinal: 9

Calculation

1. (9 - 1) mod 5 = 3.
2. Family index 3 maps to Rikta.

Result

• Family: Rikta
• Rikta flag: true

Method notes

• The family mapping is stable across Shukla and Krishna Paksha; activity suitability is not inferred here.

Contract

Owning layer: personal
Claim kind: textual-rule
Time basis: Active day or slot Tithi.

Inputs

• Tithi name
• activity preference or exclusion

Outputs

• family name
• Rikta flag
• score or exclusion reason

References and evidence

Evidence classes: textual
Verification states: needs_locator

Family mapping and parity are tested; exact source coverage remains broad.

panchangam.derived_classifications

Evidence class: textual
Verification state: needs_locator
Locator: No precise locator is registered.

Scope: Special Yogas, Panchaka labels, Khara month, Pitru Paksha, Simha-Stha, Maudhya, Anandadi Yoga, Disha Shoola, Nakshatra Mukha and Panchaka Rahita are separate traditional classifications. The group exists to expose evidence debt and grants no umbrella textual authority; each component needs its own inspected rule table and regional boundary.

Sources

• Muhurtha (Electional Astrology) — B. V. Raman; UBS Publishers' Distributors, 1993, ISBN 9788185674681, 181 catalogued pages; authority type: modern_synthesis
• Muhurta Chintamani — Rama Daivajna; Undated Sanskrit text with Hindi commentary, Internet Archive identifier muhurta-chintamani-hindi; authority type: primary_text_hindi_commentary

The complete machine-readable source registry is available in provenance.json. A regression fixture or same-code reproduction is not independent verification.

Reproduce and review

• tests/test_muhurta_finder.py
• src/scorer/__tests__/muhurta-scorer.test.ts

Run the linked tests, then the complete offline contract:

python tools/verify_project.py

Public surfaces

• python-library
• mcp
• website

Limitations

• Activity-specific use must come from the selected profile rather than a universal family ranking.

Implementation

• owner: telugu_panchangam/personal/tithi_class.py — tithi_family
• owner: telugu_panchangam/personal/slot_scorers.py — score_tithi_class
• mirror: src/muhurta-scorer.ts — muTithiFamily
• mirror: src/muhurta-scorer.ts — muScoreTithiClass

This route is generated from computations.json. Edit the registry and canonical reference prose in the same pull request as a behavior change.