Thasathi to Gregorian Calendar Conversion

Following algorithm is used to convert Thasathi date into Gregorian Date.

Let Ty=Year , Tm=Month Td=Date

Step 1: Convert Thiruvalluvar Era into Common Era

Common Year Y=Ty-30 (Before Jan 15)

Y=Ty-31 (On or After Jan 15)

Step 2: Determine Leap Index, (As per Gregorian Calendar Year)

L=0 for Normal Years

L=1 for Leap Years (Divisble by4, Not divisible by 100, Divisible by 400)

Step 3: Determine Gregorian Serial Number

G=Td +14(For First Month)

G=28*(Tm-1)+Td+15+L (For Other Months)

Cumulative Max Number of Months,

Gmax= [0 31 59 90 120 151 181 212 243 273 304 334];

if G lies in the above region we can find the month and date;

Example:

G=170

170 lies between 151 and 181, so the month is 6

date is 170-151=19.