add auditable Swiss gulika calculator

2026-07-14 18:05:53 +08:00
parent f00d0fa368
commit 7142366dc4
4 changed files with 90 additions and 6 deletions
@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+"""Swiss-Ephemeris Gulika calculator using the Prasna Marga Ghatika table."""
+from __future__ import annotations
+
+from datetime import datetime
+from typing import Any
+
+import swisseph as swe
+
+try:
+    from saham_daynight import determine_daytime
+except ImportError:
+    from scripts.saham_daynight import determine_daytime
+
+
+# Monday=0, matching datetime.weekday(). Values are the end of Saturn's share
+# measured in Ghatika from the relevant sunrise/sunset (30 Ghatika per period).
+GHATIKA_END = {
+    0: {"day": 22, "night": 6},
+    1: {"day": 18, "night": 2},
+    2: {"day": 14, "night": 26},
+    3: {"day": 10, "night": 22},
+    4: {"day": 6, "night": 18},
+    5: {"day": 2, "night": 14},
+    6: {"day": 26, "night": 10},
+}
+
+
+def _sidereal_ascendant(jd_ut: float, lat: float, lon: float) -> float:
+    swe.set_sid_mode(swe.SIDM_LAHIRI)
+    cusps, ascmc = swe.houses_ex(jd_ut, lat, lon, b"P", swe.FLG_SIDEREAL)
+    return float(ascmc[0]) % 360
+
+
+def calculate_gulika(
+    moment: datetime,
+    *,
+    lat: float,
+    lon: float,
+    tz: float,
+) -> dict[str, Any]:
+    """Return Gulika from local moment/location using Swiss sunrise and sunset."""
+    daynight = determine_daytime(moment, lat=lat, lon=lon, tz=tz)
+    is_day = bool(daynight["is_daytime"])
+    period = "day" if is_day else "night"
+    ghatika_end = GHATIKA_END[moment.weekday()][period]
+    start_jd = daynight["sunrise_jd_ut"] if is_day else daynight["sunset_jd_ut"]
+    end_jd = daynight["sunset_jd_ut"] if is_day else daynight["sunrise_jd_ut"] + 1.0
+    if end_jd <= start_jd:
+        end_jd += 1.0
+    segment_jd = start_jd + (end_jd - start_jd) * (ghatika_end / 30.0)
+    longitude = _sidereal_ascendant(segment_jd, float(lat), float(lon))
+    return {
+        "scope": "gulika_prasna_marga",
+        "status": "partial",
+        "longitude": round(longitude, 6),
+        "sign_idx": int(longitude / 30) % 12,
+        "degree_in_sign": round(longitude % 30, 6),
+        "period": period,
+        "weekday": moment.weekday(),
+        "ghatika_end": ghatika_end,
+        "segment_jd_ut": segment_jd,
+        "daynight_evidence": daynight,
+        "ayanamsa": "lahiri",
+        "rule_source": "references/prashna-complete-guide.md#3.5",
+        "boundary": "Formula is implemented from the local classical guide; external JHora/PyJHora numeric parity remains required before enabling Sphuta or verdict layers.",
+    }