moira

Moira Varga Backend Standard

Version: 1.2 Date: 2026-10-07 Status: Current engine/REST truth; bounded D60 source profiles

Governing Principle

The Moira Varga backend is a Vedic divisional-chart placement subsystem. It maps caller-supplied sidereal ecliptic longitudes into the currently implemented Shodashvarga divisions and preserves the resulting varga sign, symbol, degree, division number, and mapped varga longitude in an immutable VargaPoint.

This document reflects current implementation truth. It does not claim that the module performs tropical-to-sidereal conversion, derives chart positions, or implements every specialized school-specific varga variant.

---

Part I - Architecture Standard

1. Authoritative Computational Definitions

1.1 Varga point

A VargaPoint in Moira is:

One body’s placement inside one Vedic divisional chart, computed from one caller-supplied sidereal longitude.

Field	Meaning
varga_name	Display name of the division
varga_number	Division number, such as 9 for Navamsha
longitude	Normalized source longitude
varga_longitude	Mapped longitude in the varga sign
sign	Varga sign name
sign_symbol	Varga sign symbol
sign_degree	Degree within the varga sign
deity	Nullable named D60 enrichment; generic D60 remains null
d60_method	Actual full-position D60 convention (harmonic, pvr_textbook_linear or classical_derived_linear); null for non-D60 or unknown legacy/manual metadata
d60_source_references (property)	Applied source/derivation chain, copied to REST; empty for non-D60 or unknown manual metadata
d60_degree_attribution (property)	generic_harmonic, modern_composed, classical_derived, or null for non-D60/unknown metadata; a derived policy is not a direct classical D60 degree prescription

VargaPoint is frozen and slotted. This matches its machine contract: the result vessel is read-only once constructed. Its D60 receipt rejects a sign-only method or an inapplicable division.

1.2 Generic varga formula

The generic formula divides each 30-degree sign into n equal segments and maps the segment index through the zodiac:

segment_idx, remainder = divmod(exact_binary_longitude * n, 30)
sign_idx = segment_idx % 12
sign_degree = representable_inside_sign(remainder)

This is the active computation for:

• calculate_varga(...)
• navamsa
• saptamsa
• dashamansa
• dwadashamsa
• trimshamsa
• shashthamsha
• ashtamsha
• shodashamsha
• vimshamsha
• chaturvimshamsha
• shashtiamsha

1.3 Parashari sign-offset wrappers

The backend also implements specific sign-offset rules for five divisions:

• hora / D2
• chaturthamsha / D4
• saptavimshamsha / D27
• khavedamsha / D40
• akshavedamsha / D45

These wrappers compute the varga sign by their declared Parashari offset rule and then materialize a VargaPoint.

---

2. Layer Structure

The Varga backend is intentionally small:

P1  - Truth preservation             (VargaPoint)
P3  - Inspectability                 (__repr__)
P10 - Hardening                      (range tests, frozen vessel contract)
P12 - Public API curation            (__all__, root/vedic/classical/facade exports)

Layer boundary rules:

• All public computation functions consume sidereal longitudes.
• The module does not compute ayanamsa.
• The module does not compute chart positions.
• Wrapper functions delegate result materialization to calculate_varga(...) or _build_varga_point(...).
• A REST adapter must not hide tropical-to-sidereal reduction inside this module’s transport family.

---

3. Public Surface

All public names are declared in moira/varga.py.

Vessel

Name	Meaning
VargaPoint	Frozen result vessel for one divisional placement
D60Method	Harmonic, Santhanam sign-only, composed PVR textbook/linear or classical-derived proportional selection
D60SignResult	Frozen sign-only placement; no mapped longitude/degree

Computation functions

Function	Division	Rule
calculate_varga	arbitrary n	generic
navamsa	D9	generic
saptamsa	D7	generic
dashamansa	D10	generic
dwadashamsa	D12	generic
trimshamsa	D30	generic computational alternative
hora	D2	Parashari odd/even Cancer/Leo rule
chaturthamsha	D4	Parashari sign-offset rule
shashthamsha	D6	generic
ashtamsha	D8	generic
shodashamsha	D16	generic
vimshamsha	D20	generic
chaturvimshamsha	D24	generic
saptavimshamsha	D27	Parashari triplicity-start rule
khavedamsha	D40	Parashari odd/even Aries/Libra rule
akshavedamsha	D45	Parashari odd/even Aries/Capricorn rule
shashtiamsha	D60	harmonic default, pvr_textbook_linear or classical_derived_linear
d60_sign	D60 sign only	harmonic default, bphs_santhanam_sign, pvr_textbook_linear or classical_derived_linear

The D60 source standard owns the selected edition, sign formula, four corrected deity names, strict method applicability, strength effects and limits of continuous-degree evidence. The Santhanam source method is accepted by d60_sign, varga_sign_index at divisor 60 and Vimshopaka groups containing D60. It is rejected by full-position wrappers and facade methods before chart work. Harmonic numeric defaults are retained. The separately named PVR profile admits full positions through scalar, chart and Shodashvarga consumers with two source locators. It combines dated modern primary prescriptions; direct classical continuous-D60-degree prescription is unestablished. Its direct inputs are strict finite numbers and it cannot select another named division. Deity naming still uses the identified Santhanam table.

The classical-derived profile is also complete through the same consumers. It shares the proportional coordinates with a different reviewed source chain and an explicit Moira derivation receipt. Its adjudication separates D60 sign authority, general subdivision arithmetic, D12 fractional correspondence, Raman’s D9 degree notes and the D60 extension. Source-profile groups normalize the shared input before evaluating other divisions, including tiny negative wrap limits. This retains each division’s own sign doctrine.

---

4. Determinism and Failure Doctrine

4.1 Determinism

• Longitudes are normalized with modulo 360.
• Sign order is Aries through Pisces, index 0 through 11.
• sign_degree is always intended to remain in [0, 30).
• varga_longitude is always intended to remain in [0, 360).
• The same longitude and division always produce the same VargaPoint.

4.2 Failure doctrine

Current implementation truth:

• Existing full-position helpers retain their numeric input behavior; this package is not a general Varga input audit. The new d60_sign helper rejects bool/string/nonfinite inputs explicitly and requires an actual D60Method.
• REST transport must reject non-finite longitude inputs before calling the engine.
• VargaPoint is immutable after construction.

No dedicated validate_varga_output(...) helper is currently exposed. The current backend hardening is provided by vessel immutability, output range tests, boundary tests, and wrapper-specific rule tests.

---

Part II - Validation Codex

5. Validation Scope

The Varga backend is currently validated through:

• tests/unit/test_varga.py
• tests/unit/test_shodashvarga.py
• tests/unit/test_d60_deities.py
• tests/unit/test_vedic_chara_d60_admission.py
• tests/server/test_vedic_chara_d60_admission.py
• tests/unit/test_d60_full_position.py
• tests/server/test_d60_full_position.py
• public API surface checks in tests/unit/test_api_surface_adversarial_audit.py

6. Validation Claims

The following claims are currently verified:

1. D1 identity behavior is preserved.
2. Generic segment boundaries advance signs and reset degrees correctly.
3. 360-degree wrapping and periodicity are preserved.
4. sign_degree is scaled from segment remainder.
5. Convenience wrappers preserve declared varga names and numbers.
6. Output varga_longitude and sign_degree ranges hold across samples.
7. VargaPoint.__repr__ exposes name, division, sign, and minutes.
8. VargaPoint is immutable.
9. D2, D4, D27, D40, and D45 sign-offset rules are covered by focused tests.
10. Generic Shodashvarga wrappers preserve names, division numbers, ranges, and longitude wrapping.
11. Sign names and symbols remain consistent.

7. Validation Commands

The minimum verification slice for this standard is:

.\.venv\Scripts\python.exe -m py_compile moira\varga.py tests\unit\test_varga.py tests\unit\test_shodashvarga.py
.\.venv\Scripts\python.exe -m pytest tests\unit\test_varga.py tests\unit\test_shodashvarga.py -q
.\.venv\Scripts\python.exe -m pytest tests\unit\test_public_doctrine_surfaces.py tests\unit\test_api_surface_adversarial_audit.py -q

---

Part III - Admitted REST Surface

Eight placement routes cover generic, named, Shodashvarga, direct batches and three chart-derived shapes. The chart adapter owns tropical-to-sidereal reduction and returns its ayanamsa/context provenance. Every point preserves canonical nullable deity, applied d60_method and positional source locators through the shared serializer.

POST /v1/varga/d60/sign exposes the typed sign-only result. Seven named/full Shodashvarga request schemas admit harmonic and pvr_textbook_linear; source-only or unknown selections receive HTTP 422 before chart derivation. Vimshopaka exposes the selected D60 method for groups containing D60 and copies its actual receipt. See REST reference and the implementation receipt and full-profile receipt.

Numerical boundaries — 9 October 2026

Generic placement uses the exact integer ratio of the supplied finite binary float for one partition decision. Sign, degree and mapped longitude stay on the same half-open side of every boundary. A nonzero negative residue whose modulo rounds to360 is represented by nextafter(360,0); exact turns remain0. Booleans, nonfinite and nonnumeric values reject. Named mappings retain their own doctrine and reuse normalization/partition where appropriate. This changes numerically incorrect boundary assignments without changing source-specific D60 policy. The separate Shadbala source D7/D12/D30 helpers do not change the public harmonic selectors. Independent corpus:65,880 D1–D60 boundary cases plus4,320 explicit D60 profile consistency cases; see the repair validation receipt.

This site is open source. Improve this page.