Arudha Lagna Calculator -

Exception: AL_pre == Lagna (1) → final AL = 10th house.

# 2. Position of lord lord_house = house_positions[lord_of_lagna] arudha lagna calculator

# 5. Apply exceptions if al_pre == 1: # Lagna itself al_final = 10 elif al_pre == 7: # 7th from Lagna al_final = 4 else: al_final = al_pre Exception: AL_pre == Lagna (1) → final AL = 10th house

Let ( D = Pos_Lord \to H_L ) (forward count in zodiac order, not retrograde). ( D = (H_L - Pos_Lord) \mod 12 ); if result = 0, set ( D = 12 ). Apply exceptions if al_pre == 1: # Lagna

# 4. Preliminary AL al_pre = (lord_house + delta - 1) mod 12 + 1

If ( AL_pre = H_L ) (i.e., AL falls in Lagna itself), then AL is 10th house from Lagna . If ( AL_pre ) is exactly the 7th house from Lagna, then AL is 4th house from Lagna . 3. Algorithm for an Arudha Lagna Calculator The following pseudo-code implements the classic Parashari rule. 3.1 Pseudo-code function calculate_arudha_lagna(lagna_degrees, house_positions_of_planets): # lagna_degrees: 0-360 # house_positions: dict planet: house_number 1..12 # 1. Find Lagna sign and its lord lagna_sign = floor(lagna_degrees / 30) + 1 # 1=Aries ... 12=Pisces lord_of_lagna = get_planet_ruler(lagna_sign) # e.g., Mars for Aries

Let ( LordPos ) = house of Lagna lord (1..12). Let ( LagnaHouse = 1 ). ( D = ((1 - LordPos) \mod 12) ); if ( D == 0 ), ( D = 12 ). ( AL_pre = ((LordPos - 1 + D) \mod 12) + 1 ). If ( AL_pre == 1 ): ( AL = 10 ). Else if ( AL_pre == 7 ): ( AL = 4 ). Else ( AL = AL_pre ). End of paper. This paper can be used as both a theoretical introduction and a developer’s specification for building an accurate Arudha Lagna calculator.