Formulas for >HMS & >HR Message #1 Posted by Pekis on 8 June 2008, 5:48 p.m.
Hello,
... A bit of fun with maths ... :)
One day I've discovered these formulas from my personal work:
Decimal number > Hours, minutes and seconds
>HMS(x): (90*x+100*INT(x)+INT(60*x))/250
Ex: >HMS(pi)=3.08297335529 (i.e. 3 h 08 m 29.73... s)
Hours, minutes and seconds > decimal number
>HR(x): (250*x60*INT(x)INT(100*x))/90
Ex: >HR(3.08297335529)=3.14159265359
Are these formulas well known ?
Rem.: Beware of internal representation of some numbers !
Ex:
>HR(1.2)=1.33333333333 (i.e. 4/3)
but
>HMS(4/3) must be 1.2, and not 1.196 due to the fact that 60*1.33333333333=79.9999999998, so INT(79.9999999998)=79, even if 79.9999999998 was displayed as 80.0000 in FIX 4 !
Solution: Always round first to a fixed number of significant digits before applying INT, so 79.9999999998 is rounded first to 80.
